US President Barack Obama has said he “profoundly” regrets his army’s drone strike that killed an American and Italian aid worker in January.

The covert operation on the Afghan-Pakistan border was targeting an al-Qaeda compound, but accidentally killed the two men being held hostage by the group.

Making the operation public overnight, Mr Obama said he took “full responsibility” for the drone strike which killed Warren Weinstein, 73, and Giovanni Lo Porto, 39.

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“Based on information and intelligence we have obtained, we believe that a US counter-terrorism operation targeting an al-Qaeda compound in the Afghanistan-Pakistan border region accidentally killed Warren and Giovanni this past January,” Mr Obama said.

US aid worker Warren Weinstein. Photo: Twitter

“As president and as commander-in-chief, I take full responsibility for all our counter-terrorism operations, including the one that inadvertently took the lives of Warren and Giovanni.

“I profoundly regret what happened. On behalf of the United States government, I offer our deepest apologies to the families.”

The president confirmed the strike did successfully kill Ahmed Faruq, an American who was an al-Qaeda leader, and Adam Gadahn, an American who became a prominent member of the group.

Mr Weinstein was working as an aid worker in Pakistan when he was kidnapped from his home and taken hostage by al-Qaeda in 2011.

Italian aid worker Lo Porto disappeared in January 2012 in Pakistan.

Italian aid worker Giovanni Lo Porto. Photo: Twitter

Mr Weinstein later appeared in al-Qaeda videos in which he asked the American government, under duress, to stop drone strikes in Pakistan.

His wife, Elaine Weinstein, blamed the terrorist organisation for her husband’s death but said she was also disappointed by the American government’s effort to rescue him.

“Those who took Warren captive over three years ago bear ultimate responsibility,” Mrs Weinstein said in a statement.

“The cowardly actions of those who took Warren captive and ultimately to the place and time of his death are not in keeping with Islam and they will have to face their God to answer for their actions.

“Warren spent his entire life working to benefit people across the globe and loved the work that he did to make people’s lives better.”