China said on Monday that US high altitude balloons had flown over its airspace without permission more than 10 times since the beginning of 2022, widening a diplomatic row after the US military shot down what it says was a Chinese spy balloon.

"Since last year, the US's high-altitude balloons have undergone more than 10 illegal flights into Chinese airspace without the approval of the relevant Chinese departments,” Chinese foreign ministry spokesperson Wang Wenbin said at a regular briefing in Beijing in response to a question.

Wang did not specifically describe the balloons as military or for espionage purposes and did not provide further details.

Asked how China had responded to such incursions into its airspace, Wang said its responses had been “responsible and professional”.

The US defense department did not immediately respond to a request for comment.

China's assertion comes after the United States shot down what it says was a Chinese spy balloon off the coast of South Carolina on February 4 after it had drifted across the continental United States for days.

In resposne to the Chinese balloon, the United States postponed a visit to Beijing by Secretary of State Antony Blinken.

China says the balloon was a civilian research craft that had mistakenly blown off course and accused the United States of overreacting.

"The first thing the U.S. side should do is to look at itself, to change its ways, not to smear and incite confrontation,” Wang said.

In recent days, the US military has shot down three other flying objects over North America.

Wang said he had no information on the latest three objects shot down by the United States.