China says US sent more than 10 balloons into airspace

China's foreign ministry says the US has flown balloons into its airspace more than 10 times in the past year.

The accusation comes after the US on 4 February shot down a suspected spy balloon over its airspace, which China said was a civilian balloon.

Relations between the two countries have since deteriorated. In recent days, the US says it has also shot down a number of other devices.

Questioned on Monday, Beijing said the US had intruded several times.

"It's not uncommon as well for the US to illegally enter the airspace of other countries," said foreign ministry spokesman Wang Wenbin at a regular press briefing.

"Since last year alone, US balloons have illegally flown above China more than 10 times without any approval from Chinese authorities," he added.

He said Beijing had responded to the incursions in a "responsible and professional" manner. He did not disclose further details.

"If you want to know more about US high-altitude balloons illegally entering China's airspace, I suggest you refer to the US side," he said.

Washington is yet to respond to the allegations from Beijing.

On Sunday, the US ordered a fourth object to be downed in Michigan near the Canadian border. It was described by defence officials as an unmanned "octagonal structure" with strings attached to it.