"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," President Biden said to applause during Tuesday evening's State of the Union address.
A US fighter jet on Saturday shot down what the Pentagon called a Chinese surveillance balloon after it floated out over the Atlantic Ocean, with the military saying it had waited until a point when the debris could not hurt people on the ground.
The episode led US Secretary of State Antony Blinken to postpone a visit to Beijing aimed at reducing tensions as he accused China of violating US sovereignty.
Defense Secretary Lloyd Austin requested a secure call with his Chinese counterpart Wei Fenghe immediately after the shootdown, Brigadier General Pat Ryder said.
"Unfortunately, the PRC has declined our request. Our commitment to open lines of communication will continue," Ryder said, referring to the People's Republic of China.
General Glen VanHerck, head of the US Northern Command, said the balloon itself was some 60 meters tall and carried a payload weighing several thousand pounds that was roughly the size of a regional jet aircraft, he said.
VanHerck said the balloon debris would be carefully studied.
"I will tell you that certainly the intel community along with the law enforcement community that works this under counterintelligence will take a good look at it," he said.
China says the balloon was an errant weather observation aircraft with no military purpose. But Washington has described it as a sophisticated high-altitude spying vehicle which reportedly traversed over several top-secret military sites.
Biden's speech 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 also said it was "opposed to using competition to define the entire Sino-US relationship."