Sensors from the first suspected Chinese spy balloon have been recovered from the Atlantic Ocean, the US military says.

The balloon spent a week flying over the US and Canada before President Joe Biden ordered it to be shot down on 4 February off the South Carolina coast.

The US Northern Command said in a statement: "Crews have been able to recover significant debris from the site, including all of the priority sensor and electronics pieces identified as well as large sections of the structure."

About 30-40ft (9-12m) of the balloon’s antenna array are among the items found, according to CBS, the BBC’s US partner.

In this U.S. Navy handout, Sailors assigned to Assault Craft Unit 4 prepare material recovered in the Atlantic Ocean from a high-altitude balloon for transport to federal agents at Joint Expeditionary Base Little Creek 10 February 2023

The FBI is examining the items after The White House said it has determined that China has a "high-altitude balloon programme" for intelligence gathering. However, China said the balloon was a weather-monitoring airship that had blown astray.

Since the balloon was taken down, a further three unidentified objects have also been shot down over the North American airspace and efforts are being made to retrieve the remains.

The US has admitted that much about the most recent unmanned objects remains unknown, including how they stay aloft, who built them and whether they may have been collecting intelligence.

The US has not yet recovered any debris from the most recent three objects - one of which fell off the coast of Alaska in ice and snow. Another was shot down over the Yukon territory in Canada and one was shot down over Lake Huron on the US-Canada border.

The balloon shot down over South Carolina was described by officials as the size of three buses, while the second object, over Alaska, was described as the size of a "small car".

The third object, over the Yukon, was "cylindrical" and the fourth, over Michigan, was said to be "octagonal" with strings attached. Officials say the slow-moving objects have been smaller than the first balloon and may be difficult for military pilots to target.

Canadian Prime Minister Justin Trudeau said the four aerial objects were somehow connected - without explaining further.

He said: "Obviously there is some sort of pattern in there, the fact we are seeing this in a significant degree over the past week is a cause for interest and close attention."

China has said US high-altitude balloons have flown over its airspace more than 10 times over the past year - a claim that Washington rejects.

Chinese spy balloon: US recovers ‘priority sensors’ from debris of suspected spy object shot down