President Joe Biden on Monday told reporters that it was "always" his position to shoot down a suspected Chinese spy balloon, a comment which comes amid heigtened tensions between Washington and Beijing over the incident.

The U.S. shot down the balloon off the Carolina coast on Saturday after it traversed sensitive military sites across North America.

China earlier Monday accused the United States of indiscriminate use of force in shooting down a suspected Chinese spy balloon, saying it "seriously impacted and damaged both sides' efforts and progress in stabilizing Sino-U.S. relations." China insisted the flyover was an accident involving a civilian aircraft.

Vice Foreign Minister Xie Feng said he lodged a formal complaint with the U.S. Embassy on Sunday over the "U.S. attack on a Chinese civilian unmanned airship by military force."

"However, the United States turned a deaf ear and insisted on indiscriminate use of force against the civilian airship that was about to leave the United States airspace, obviously overreacted and seriously violated the spirit of international law and international practice," Xie said.

But State Department spokesperson Ned Price on Monday pushed back against the assertion that the U.S. "overreacted," telling reporters during a Monday press briefing that the blame "falls to the [People's Republic of China] for engaging in what was ultimately an inappropriate and irresponsible or unacceptable act."

"The PRC knows precisely what this was. The PRC knows precisely why this was in our airspace," Price added. "And ultimately, the PRC knows precisely why we did what we did."

Returning to the White House on Monday, Biden said that it was "always my position" to shoot down the balloon once it entered U.S. airspace, dispeling the notion that he was only going to do so because it was made public.

"Once it came over to the United States from Canada, I told the Defense Department I wanted to shoot it down as soon as it was appropriate," Biden said. "They concluded we should not shoot it down over land, it was not a serious threat and we should wait until it got across the water."

The presence of the balloon in the skies above the U.S. dealt a severe blow to already strained U.S.-Chinese relations that have been in a downward spiral for years. It prompted Secretary of State Antony Blinken to abruptly cancel a high-stakes Beijing trip aimed at easing tensions.

"The discovery of this high altitude surveillance balloon in the days that preceded the Secretary's visit, of course, undermined the point of that visit," Price said Monday. "We would not have been able to conduct the important business that Secretary Blinken was looking forward to doing on the ground in Beijing in that context." 

Price stressed that the visit was not cancelled, rather postponed, by the presence of the surveillance balloon, "until such a time where it'd be appropriate for the Secretary to travel to Beijing, to have the type of meeting that we hope to have – a meeting that could help to establish a floor under the relationship and a meeting where we could discuss everything that's of interest to us, and many issues that are of interest to the rest of the world as well."

Xie repeated China's insistence that the balloon was a Chinese civil unmanned airship that blew into U.S. airspace by mistake, calling it "an accidental incident caused by force majeure."

China will "resolutely safeguard the legitimate rights and interests of Chinese companies, resolutely safeguard China's interests and dignity and reserve the right to make further necessary responses," he said.

But Price disputed claims that the balloon flew off-course accidentally or that it was a result of incompetence from China, saying: "I think those explanations just ring hollow to us. They ring as hollow as the idea that this was some sort of weather balloon."

President Joe Biden issued the shootdown order after he was advised that the best time for the operation would be when it was over water, U.S. officials said. Military officials determined that bringing down the balloon over land from an altitude of 60,000 feet would pose an undue risk to people on the ground.

"What the U.S. has done has seriously impacted and damaged both sides' efforts and progress in stabilizing Sino-U.S. relations since the Bali meeting," Xie said, referring to a recent meeting between Biden and his Chinese counterpart, Xi Jinping, in Indonesia that many hoped would create positive momentum for improving ties that have plunged to their lowest level in years.

Foreign Ministry spokesperson Mao Ning provided no new details on Monday, repeating China's insistence that the object was a civilian balloon intended for meteorological research, had little ability to steer and entered U.S. airspace by accidentally diverging from its course. She also did not say what additional steps China intended to take in response to Washington's handling of the issue and cancellation of Blinken's trip, which would have made him the highest-ranking U.S. official to visit since the start of the COVID-19 pandemic.

"We have stated that this is completely an isolated and accidental incident caused by force majeure, but the U.S. still hyped up the incident on purpose and even used force to attack," Mao said at a daily briefing. "This is an unacceptable and irresponsible action."

Balloons thought or known to be Chinese have been spotted from Latin America to Japan. Japanese Deputy Chief Cabinet Secretary Yoshihiko Isozaki told reporters Monday that a flying object similar to the one shot down by the U.S. had been spotted at least twice over northern Japan since 2020.

"We are continuing to analyze them in connection with the latest case in the United States," he said.

Mao confirmed that a balloon recently spotted over Latin American was Chinese, describing it as a civilian airship used for flight tests.

"Affected by weather and due to its limited self-control ability, the airship severely deviated from its set route and entered the space of Latin America and the Caribbean by accident," Mao said.

Washington and Beijing are at odds over a range of issues from trade to human rights, but China is most sensitive over alleged violations by the U.S. and others of its sovereignty and territorial integrity.

Beijing strongly protests U.S. military sales to Taiwan and visits by foreign politicians to the island, which it claims as Chinese territory, to be recovered by force if necessary.

It reacted to a 2022 visit by then-U.S. House Speaker Nancy Pelosi by firing missiles over the island and staging threatening military drills seen as a rehearsal for an invasion or blockade. Beijing also cut off discussion with the U.S. on issues including climate change that are unrelated to military tensions.

Last week, Mao warned Pelosi's successor, House Speaker Kevin McCarthy, not to travel to Taiwan, implying that China's response would be equally vociferous.

"China will firmly defend its sovereignty, security and development interests," Mao said. McCarthy said China had no right to dictate where and when he could travel.

China also objects when foreign military surveillance planes fly off its coast in international airspace and when U.S. and other foreign warships pass through the Taiwan Strait, accusing them of being actively provocative.

In 2001, a U.S. Navy plane conducting routine surveillance near the Chinese coast collided with a Chinese fighter plane, killing the Chinese fighter pilot and damaging the American plane, which was forced to make an emergency landing at a Chinese naval airbase on the southern Chinese island province of Hainan. China detained the 24-member U.S. Navy aircrew for 10 days until the U.S. expressed regret over the Chinese pilot's death and for landing at the base without permission.

The South China Sea is another major source of tension. China claims the strategically key sea virtually in its entirety and protests when U.S. Navy ships sail past Chinese military features there.

At a news conference Friday with his South Korean counterpart, Blinken said "the presence of this surveillance balloon over the United States in our skies is a clear violation of our sovereignty, a clear violation of international law, and clearly unacceptable. And we've made that clear to China."

"Any country that has its airspace violated in this way I think would respond similarly, and I can only imagine what the reaction would be in China if they were on the other end," Blinken said.

China's weather balloon explanation should be dismissed outright, said Oriana Skylar Mastro, an expert on Chinese military affairs and foreign policy at Stanford University.

"This is like a standard thing that countries often say about surveillance assets," Mastro said.

China may have made a mistake and lost control of the balloon, but it was unlikely to have been a deliberate attempt to disrupt Blinken's visit, Mastro said.

For the U.S. administration, the decision to go public and then shoot down the balloon marks a break from its usual approach of dealing with Beijing on such matters privately, possibly in hopes of changing China's future behavior.

However, Mastro said, it was unlikely that Beijing would respond positively.

"They're probably going to dismiss that and continue on as things have been. So I don't see a really clear pathway to improved relations in the foreseeable future."