Biden talks tough on China 'threat'

President Joe Biden vowed Tuesday he would not hesitate to defend US interests against China after he ordered the downing of a suspected surveillance balloon, but delivering his State of the Union address, he kept the door open to cooperation.

In the annual speech to assembled lawmakers, Biden called for US investment in the military, technology and alliances to take on the country widely viewed as the chief US competitor.

"I'm committed to work with China where it can advance American interests and benefit the world," Biden said.

"But if China threatens our sovereignty, we will act to protect our country. And we did, as we made clear last week," he added, referring to when a US fighter jet on Saturday shot down what the Pentagon called a Chinese surveillance balloon after it floated out over the Atlantic Ocean.

Biden said that "winning the competition" with China should unite Americans. "We are investing to make America stronger - investing in American innovation, in industries that will define the future that China intends to be dominating."

But Biden steered clear of hawkish language as he mentioned by name his Chinese counterpart, Xi Jinping, whom he met at length in November in Indonesia.

Biden said he told Xi that "we seek competition, not conflict."

In a foreign ministry statement issued after Biden's address, China vowed to "firmly defend" its interests but said it was "opposed to using competition to define the entire Sino-US relationship."

It urged the United States to "pursue a positive and pragmatic China policy, and work with China to push Sino-US relations back to the track of stable development."

China was one of the few foreign policy issues mentioned by Biden in a more than one-hour speech that comes as he prepares for a likely run for a second term.