In his State of the Union address on Tuesday night, Trump said he had directed the defence secretary, James Mattis, “to reexamine our military detention policy and to keep open the detention facilities at Guantánamo Bay”. He added that he expected that “in many cases” captured terrorists would be sent to the camp.

The Trump executive order instructs Mattis, in consultation with the secretary of state and other officials, to deliver a new policy on battlefield detentions, “including policies governing transfer of individuals to US Naval Station Guantánamo Bay” within 90 days.

It is the latest in a long series of policies pursued by Barack Obama that Trump has reversed. Obama signed an order calling for Guantánamo Bay to be closed on his second day in office in 2009, but he was never able carry out that policy to its conclusion.

Obama argued that maintenance of an detention facility beyond the reach of US law undermined American global leadership on human rights. In his speech on Tuesday night however, Trump said that the move to close Guantánamo reflected softness in the fight against terrorism. And he suggested detention was second best to killing terrorists.

“Terrorists who do things like place bombs in civilian hospitals are evil,” Trump said. “When possible, we have no choice but to annihilate them. When necessary, we must be able to detain and question them. But we must be clear: Terrorists are not merely criminals. They are unlawful enemy combatants. And when captured overseas, they should be treated like the terrorists they are.”

He added: “In the past, we have foolishly released hundreds of dangerous terrorists, only to meet them again on the battlefield – including the Isis leader, al-Baghdadi, who we captured but who we had who we release.”

Obama’s adversaries had claimed that Abu Bakr al-Baghdadi had been released from an Iraqi prison facility called Camp Bucca in 2009. However, the insurgent who went on to lead the Islamic State, was released by a military review board in 2004.

Trump did not announce he was about to order the transfer of new prisoners to Guantánamo Bay, and a leaked state department cable to embassies abroad said there were no immediate plans for transfer to Guantánamo. But the president left that option open in his speech.

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