Trump tearing up Iran deal would be 'height of folly', says CIA director

The CIA's outgoing director John Brennan has said it would be the "height of folly" for US president-elect Donald Trump to tear up Washington's deal with Tehran because it would make it more likely that Iran and others would acquire nuclear weapons.

"First of all, for one administration to tear up an agreement that a previous administration made would be unprecedented," he said.

"It could lead to a weapons programme inside of Iran that could lead other states in the region to embark on their own programmes," Brennan said in an interview with the BBC on Wednesday.

"So I think it would be the height of folly if the next administration were to tear up that agreement."

Trump has repeatedly threatened to scrap the Iran deal.

Brennan also said that in dealing with the Syrian crisis, Trump should be cautious in trying to work with Russia.

He said both the Syrian government and the Russians were responsible for an "outrageous" slaughter of civilians.

The CIA director said he believed the US needed to continue to provide support to help rebels withstand an "onslaught" carried out by Syria, Iran, Hezbollah and Russia.

"I hope there is going to be an improvement in relations between Washington and Moscow," he said, but added: "President-elect Trump and the new administration need to be wary of Russian promises. 

"Russian promises in my mind have not given us what it is that they have pledged."