President Biden said the United States shot down a Chinese balloon as it floated off the country's southeastern coast on Saturday.

Earlier the US government had ordered a halt to flights around the South Carolina coast due to what it called an undisclosed "national security effort."

China had earlier expressed regret that an "airship" used for civilian meteorological and other scientific purposes had strayed into US airspace after being blown off-course.

China's foreign ministry said on Saturday that the flight of the "airship" over the United States was a force majeure accident.

It accused US politicians and media of taking advantage of the situation to discredit Beijing.

Washington has called the balloon a "clear violation" of US sovereignty.

US military leaders earlier this week had advised against shooting down the balloon when it was over Montana due to the risk of falling debris, officials said.

The US Federal Aviation Administration (FAA) paused departures and arrivals at three airports on Saturday, including Myrtle Beach International Airport on the South Carolina coast because of a "national security effort."

The FAA issued a temporary flight restriction to clear airspace around the South Carolina coast. The notice blocked flights to more than 260 square kilometres -- mostly over the Atlantic Ocean, according to a document posted by the FAA. The notice warned the military could use deadly force if airplanes violate the restrictions and do not comply with orders to leave.

The Chinese balloon prompted US Secretary of State Antony Blinken to postpone a visit to China this week that had been expected to start on Friday. (Reuters)