Reported plans for the upcoming trip, which first appeared last week in the Financial Times quoting officials said to have knowledge of the matter, caused an immediate stir both in Washington and Beijing. The world’s top two powers scrambled to react to what would be the first visit of a House of Representatives leader to Taiwan in a quarter of a century. With U.S.-China tensions particularly high recently, Chinese officials have issued warnings in public and private against such travel.

“The Chinese side has repeatedly made clear to the U.S. side our serious concern over Speaker Pelosi’s potential visit to Taiwan and our firm opposition to the visit,” Chinese Foreign Ministry spokesperson Zhao Lijian told reporters Monday in comments also shared with Newsweek by the Chinese embassy in Washington.

“We are fully prepared for any eventuality. If the U.S. side insists on making the visit, the Chinese side will take firm and strong measures to safeguard our sovereignty and territorial integrity,” he added. “The U.S. must assume full responsibility for any serious consequence arising thereof.”

President Joe Biden has publicly vowed on three occasions to defend Taiwan in the event of a Chinese attack, only to have his administration repeatedly emphasize that there was no change in the U.S. policy on the issue. He expressed reservations regarding the trip on Wednesday, citing Pentagon advice.

“I think that the military thinks it’s not a good idea right now,” the president told reporters, “but I don’t know what the status of it is.”

Reached for comment, a Pentagon spokesperson told Newsweek “it wouldn’t be appropriate to comment on any congressional travel possibilities.”

“In general, we regularly provide information to members of Congress considering travel as part of their national security oversight responsibilities,” the spokesperson said. “As a reminder, Congress is an independent branch of government under our Constitution and members make independent decisions about travel.”

The White House offered a similar response on Monday, as Press Secretary Karine Jean-Pierre told reporters that, while members of Congress were advised on “geopolitical and security considerations” when it came to foreign travel, they ultimately “make their own decisions.”

The following day, National Security Council Coordinator for Strategic Communications John Kirby also said the decision was up to Pelosi, but “there’s always a measure of security support, wherever she goes, that’s tailored to the environment.” This was especially so as “the speaker is in the line of succession, and so when she travels overseas, her security is important to U.S. national security, and we take those obligations seriously.”

“We work closely with her staff to make sure that she has all the context, all the information, all the facts that she needs to make the best decisions about her travel and we continue to do that,” Kirby said Tuesday.

Asked about the last time such information was conveyed to the Speaker’s office, Kirby it happened “in recent days.”

Pelosi has so far deflected media efforts to confirm her travel plans. A spokesperson for her office told Newsweek that “we cannot confirm or deny international travel in advance due to long-standing security protocols.”

Reacting to the reports, however, the speaker said Thursday that “it was important for us to show support for Taiwan” while ultimately leaving it up to the island itself whether it would want to seek independence from China.

Pelosi said Biden had not conveyed to her directly any concerns over the trip, but added that “what the president was saying is maybe the military was afraid our plane would get shot down, or something like that, by the Chinese.”

While the administration remained hesitant to weigh in, some conservatives who have otherwise been critical of Pelosi welcomed the reports.

Among them was Newt Gingrich, who in April 1997 as House Speaker became the highest-ranking U.S. official to have ever visited Taiwan. Speaking on Monday at the America First Policy Institute, which was founded by former Trump advisers Brooke Rollins and Larry Kudlow, Gingrich said he felt “very strongly that Speaker Pelosi should go to Taiwan,” eliciting applause from the audience.

He said the current House leader “should take a bipartisan delegation” as he did 25 years ago. After Beijing’s initial outrage toward his decision at the time, Gingrich said Chinese officials “begrudgingly accepted” the move, as long as he did not depart directly from a planned trip to China for Taiwan, which the speaker then visited after a stop in Japan in-between.

That trip also came at a time of heightened frictions between Beijing and Washington. Just a year earlier, China fired the second of two sets of missiles, and then-U.S. President Bill Clinton ordered two aircraft carrier groups into the Taiwan Strait. The events were part of what became known as the Third Taiwan Strait Crisis, which began a year earlier when then-President Lee Teng-hui of Taiwan was granted travel to the U.S. to speak at a graduation ceremony of his alma mater, Cornell University.

While the crisis dissipated without the violence wrought by the first two Taiwan Strait Crises in the 1950s, the question of the island’s sovereignty remains unresolved, and continues to be a key point of contention in U.S.-China relations.

Taiwan, officially the Republic of China, has managed its affairs autonomously since becoming a haven for nationalists fleeing the Communist victory that established the People’s Republic of China in 1949. Both governments have claimed to be the legitimate representative of China, and Beijing has vowed to enforce its claim through military action if diplomacy proved fruitless.

Washington maintained official diplomacy with Taipei for three decades, until shifting relations to Beijing in 1979 as part of a series of joint statements that became known as the Three Communiqués, reached between 1972 and 1982. The U.S. and Taiwan maintained informal political and military ties in line with the Taiwan Relations Act and the Six Assurances established during this same time period.

State Department spokesperson Ned Price told reporters Monday that U.S. officials had no opinion on Pelosi’s trip because it remained “hypothetical.” But he also asserted that the Biden administration’s policies remained in line with the documents that have guided Washington’s relationships with Beijing and Taipei for decades.

“We remain committed to maintaining cross-strait peace and stability and our ‘One-China’ policy, which is guided, as you know, by the Taiwan Relations Act, the three Joint Communiques, and the Six Assurances,” Price said. “We of course don’t have diplomatic relations with Taiwan or support Taiwan independence, but we have a robust, unofficial relationship as well as abiding interest in maintaining peace and stability across the Taiwan Strait.”

This unofficial relationship was expanded under then-President Trump, who just weeks after the 2016 election broke precedent by accepting a call from Taiwanese President Tsai Ing-wen. His administration would further promote U.S.-Taiwan interactions through the Taiwan Travel Act signed into law in March 2018.

Biden too eschewed tradition early on by inviting Taiwan’s de-facto ambassador to the U.S. to his inauguration last year. A day before the event, his top diplomat, Secretary of State Antony Blinken, testified before Congress that “President Trump was right in taking a tougher approach to China,” even if Blinken did “disagree very much with the way that he went about it in a number of areas.”

And though speculation has only recently emerged that Biden may roll back Trump’s trade war-era tariffs against China to combat rising inflation at home, his administration has only doubled down on other moves viewed as provocative by Beijing, such as accusing China of “genocide” in its treatment of the mostly Muslim Uyghur minority in the northwestern Xinjiang, and introducing sanctions against Chinese officials over these alleged abuses and others.

Biden has also continued to send warships through the disputed Taiwan Strait, where the Chinese People’s Liberation Army has conducted military activity as well, including regular warplane flights through Taiwan’s claimed Air Defense Identification Zone, accompanied by President Xi Jinping’s vows to retake the island. The Biden administration has said it sought to balance U.S.-China relations based on areas of “cooperation, competition and confrontation,” though the two sides remain at serious odds even after a series of high-level meetings held in recent months, including virtual talks between Xi and Biden.

And as reports of Pelosi’s possible plans put the region on edge, Taipei also held air-raid drills Monday in order to simulate a “wartime situation” coinciding with the annual Han Kuang military exercises that saw live-fire training in the tense seas and skies of the Taiwan Strait.

Reached for comment regarding Pelosi’s potential travel, the Taipei Economic and Cultural Office in New York referred Newsweek to Taiwan Foreign Ministry spokesperson Joanne Ou’s response to media questions on Thursday.

Ou said at the time that the ministry was “aware” of the reports, but “has not received relevant information of Speaker Pelosi’s visit to Taiwan.”

“The Ministry of Foreign Affairs emphasized that Taiwan and the United States have good mutual trust and smooth communication channels,” Ou said. “With regard to inviting U.S. congressmen to visit Taiwan, it has always been a long-term focus of the Ministry of Foreign Affairs and the representative office in the United States.”

Taiwan has received a number of other high-profile U.S. guests since Biden took office. In April, a bipartisan delegation of six lawmakers, including influential Democratic Senate Foreign Relations Committee Chair Bob Menendez, arrived on a surprise visit to the island. A month earlier, a delegation of former officials arrived on the island, soon followed by Trump’s former State Department chief, Mike Pompeo, who on Sunday offered to return to join Pelosi on a trip to “freedom-loving Taiwan.”

Both visits drew the ire of Beijing, which then too threatened to take “strong measures” to ensure China’s sovereignty was not violated, though the visits took place without incident.

But the high-profile nature of Pelosi’s potential trip, matched with China’s significant rise in power and global status, could spark a flashpoint. On Tuesday, Chinese Defense Ministry spokesperson Senior Colonel Tan Kefei issued yet another warning directly from the People’s Liberation Army.

“As the ’number three’ of the U.S. government,” Tan said, “if Speaker Pelosi visits Taiwan, it would seriously violate the one-China principle and the stipulations in the three China-U.S. Joint Communiqués, seriously harm China’s sovereignty and territorial integrity, and seriously damage the political foundation of China-U.S. relations.”

“It will inevitably result in extremely serious damage to the relations between the two countries and the two militaries,” he added, “and lead to further escalation of the tensions across the Taiwan Strait.”

In his own remarks Tuesday, Kirby criticized Tan’s remarks and that of other Chinese officials issuing warnings in response to reports that Pelosi was planning to travel to Taiwan.

“Frankly, that kind of rhetoric is unnecessary and uncalled for,” Kirby said. “There’s no trip to speak to and rhetoric of that kind only escalates tensions in a completely unnecessary manner. So we find that unhelpful and certainly not the least bit necessary given the situation.”

Newsweek has reached out to the office of former President Trump for comment.

Newsweek White House correspondent Daniel Bush contributed to the reporting of this story.

This article has been updated to include comments from White House National Security Council Coordinator for Strategic Communications John Kirby and a spokesperson for House Speaker Nancy Pelosi’s office.