The director of the U.S. intelligence agency has issued warnings over the dangers of scrapping the Iran nuclear deal, as well as trusting what he called "Russian promises."
CIA Director John Brennan warned U.S. President-elect Donald Trump that abandoning the nuclear deal with Iran would be "disastrous" and "the height of folly."
"I think it would be disastrous, it really would," the BBC quoted Brennan as saying on November 30 in an interview.
International sanctions against Iran were eased in January following a nuclear deal with world powers that curbed the country's controversial nuclear program.
But Trump, who will take office in January, said during campaigning for the White House that it was a "terrible" deal that only benefited Iran and that he would "tear it up" if he were elected president.
However, he has conceded that it would be hard to destroy a deal enshrined in a United Nations resolution.
Brennan told the BBC that scrapping the agreement would risk strengthening hard-liners in Iran and risk other states pursuing nuclear programs in response to a renewed Iranian effort.
"I think it would be the height of folly if the next administration were to tear up that agreement," he said.
The CIA director also advised Trump and the new administration "to be wary of Russian promises," blaming Moscow for much of the suffering in Syria.
Brennan said that Russia -- a key ally of Syrian President Bashar al-Assad -- continues to hold the key to Syria's future.
But he also expressed skepticism about the Russia's willingness to come to any kind of deal "until they are able to achieve as much tactical battlefield successes as possible."
The CIA director added that he believes Washington needs to continue supporting moderate rebels fighting the Damascus regime to help them withstand what he called an "onslaught" carried out by Syria, Iran, Hizballah, and Russia.
During campaigning for the White House, Trump suggested his administration may try to work more closely with Moscow on a number of issues, such as the fight against the Islamic State extremist group.
Brennan will step down in January after four years leading the U.S. intelligence agency.