China has returned the US drone they seized unlawfully back to the Americans after "friendly" talks.

The unmanned underwater drone, which was deployed by the oceanographic survey ship USNS Bowditch, was taken last week in international waters by a Chinese Navy vessel.

The same ship returned the drone near to the spot in the South China Sea, close to the Philippines, where it had been taken on 15 December, the Pentagon spokesman Peter Cook said.

The drone was handed over to missile destroyer USS Mustin in international waters about 50 miles north-west of Subic Bay, according to Mr Cook.

The US said the drone was being operated by civilian contractors collecting unclassified scientific data in international waters. Officials say a non-combat ship was recovering two drones when a Chinese ship approached, launched a small boat and picked up one of them.

China's defence ministry said in a statement that it handed the drone back after "friendly consultations".

Mr Cook said the US will continue to investigate the incident.

President-elect Donald Trump said last week, China should keep the drone.

In a tweet, he wrote: "We should tell China that we don't want the drone they stole back.- let them keep it!"