Republican Donald Trump said he would institute “extreme vetting” of new immigrants if he wins the presidential election, in his foreign policy speech in Youngstown, Ohio.

As president, he said, he would ask the US State Department and Department of Homeland Security to identify regions of the world that remain hostile to the United States and where screening might not be enough to catch those who pose a threat.

Mr Trump invoked comparisons of the fight against the Islamic State to the dangers of the Cold War.

“In the cold war we had an ideological screening test, the time is overdue to develop a new screening test for the threats we face today.”
Donald Trump

He also took aim at President Barack Obama, labelling him as “an incompetent president”.

He accused the Mr Obama of creating a “vacuum to let terrorism grow and thrive” for his views on Iran and for allowing the spread of terrorism leading to the rise of IS.

Mr Trump also said he’ll work with NATO and wage a multi-front “military, cyber and financial” war to defeat Islamic State.

“We will also work closely with NATO on this new mission,” said Trump, whose remarks about the defence organisation earlier this summer drew heavy criticism from allies and even some of his fellow Republicans.

But what he called the organisation’s newly adopted approach to fighting terrorism had led him to change his mind and he no longer considered NATO “obsolete”, Trump said.

He was apparently referring to reports the alliance is moving toward creating a new intelligence post in a bid to improve information sharing.

NATO has been dealing with terrorism as an alliance since after the September 11, 2001, attacks on the US.

Watch some of Mr Trump’s speech: