An airstrike authorized by the Trump administration against an al Queda outpost in Yemen has killed a former detainee from the U.S. detention center at Guantanamo Bay, Cuba who was released in 2009.

"We can confirm the death of a former Guantanamo Bay detainee, Yasir al Silmi," said Navy Captain Jeff Davis, a Pentagon spokesman.

This means that President Donald Trump has killed a foreign combatant that was released under the authority of Barack Obama.

However, Obama is not the only one who released an enemy combatant who would eventually return to the battlefield. George W. Bush set free an Islamic fighter in 2004 who detonated a car bomb outside an Iraqi base in Tal Gaysum, south-west of Mosul last month.

He had been captured in the Middle East by the United States in 2001, before being sent to Guantanamo Bay. The British-born man was freed from the detention center and was given £1 million from the British taxpayers on the grounds that he was tortured.