US President Joe Biden on Tuesday delivered his second State of the Union address, speaking before a divided Congress after Republicans took control of the House in November's midterm elections.

Biden touted the economic accomplishments of his administration and noted recent strong economic numbers.

The president declared that while the nation was "bruised" by COVID-19, "our democracy remains unbowed and unbroken".

"We are the only country that has emerged from every crisis stronger than when we entered it. That is what we are doing again," he said.

With House Speaker Kevin McCarthy seated behind him, Biden offered to work with Republicans. McCarthy sat during almost all of Biden's speech, sometimes applauding.

"If we could work together in the last Congress, there is no reason we can't work together in this new Congress," Biden said.

"The people sent us a clear message," he said. "Fighting for the sake of fighting, power for the sake of power, conflict for the sake of conflict, gets us nowhere.

"And that's always been my vision for the country: to restore the soul of the nation, to rebuild the backbone of America: the middle class, to unite the country," Biden said. We've been sent here to finish the job."

On relations with China, Biden reiterated that Washington doesn't seek conflict with Beijing and will work with the second-largest economy in areas where interests align.

"We made clear and I made clear in my personal conversations, which have been many with President Xi, that we seek competition, not conflict," he said, adding that he will "make no apologies" that the US is investing in innovation, industries and alliances to make America stronger.

Biden also said the US is committed to working with China "where we can advance American interests and benefit the world", but added, "Make no mistake about it, as we made clear last week, if China threatens our sovereignty, we will act to protect our country, and we did."

He was apparently referring to the drama around a Chinese meteorological research balloon, which was shot down by a US fighter jet on Saturday after it had been blown across the country by strong winds.

On Tuesday, Xu Xueyuan, chargé d'affaires of the Chinese embassy in the US, lodged a stern representation with senior officials of the US State Department and White House National Security Council on the US attack on a Chinese unmanned civilian airship.

Xu pointed out that the unintended entry of the airship was an entirely unexpected, isolated incident caused by force majeure.

Biden reiterated his focus on middle class jobs.

"Amid the economic upheaval of the past four decades too many people have been left behind or treated like they're invisible. Maybe that's you watching at home. You remember the jobs that went away," Biden said. "Jobs are coming back, pride is coming back because of the choices we made in the last two years. This is a blue-collar blueprint to rebuild America and make a real difference in your lives."

Biden also called for better policing to prevent violence and said police must be held accountable if they violate rights.

Seated in the gallery as invited guests were Tyre Nichols' family, including his mother RowVaughn Wells and stepfather Rodney Wells. Nichols, 29, was beaten by five police officers in Memphis, Tennessee, and died three days later on Jan 10.

The address had some testy moments when Republicans booed after Biden said some of them wanted to do away with Social Security and Medicaid.

"Instead of making the wealthy pay their fair share, some Republicans want Medicare and Social Security to sunset every five years. That means if Congress doesn't vote to keep them, those programs will go away," Biden said.

"Other Republicans say if we don't cut Social Security and Medicare, they'll let America default on its debt for the first time in our history.

He later concluded after the exchange that they were in agreement on preserving the entitlement programs.

Biden also acknowledged Brandon Tsay, who disarmed a gunman in Monterey Park, California, two weeks ago during a Lunar New Year celebration.

"Ban assault weapons now," he said, adding that he led efforts to do so in 1994 as part of that crime bill.

As Biden pleaded with Congress to pass his immigration legislation, some Republicans appeared to chant "secure the border".

Arkansas Governor Sarah Huckabee Sanders, who once served as press secretary for former president Donald Trump, gave the Republican response.

"In the radical left's America, Washington taxes you and lights your hard-earned money on fire. But you get crushed with high gas prices, empty grocery shelves, and our children are taught to hate one another on account of their race," Sanders said in excerpts released ahead of her televised remarks.

Heng Weili in New York and agencies contributed to this story.