The US spy chief said Washington had reason to worry about who might replace President Bashar al-Assad if his government fell, given the rise of the Islamic State group and other jihadists in Syria.
“I think that’s a legitimate concern,” Brennan said when asked if the US government feared who might succeed Assad.
Speaking at an event at the Council on Foreign Relations, he said that “extremist elements” including the IS group and Al-Qaeda veterans are “ascendant right now” in some parts of Syria.
“The last thing we want to do is allow them to march into Damascus.”
Brennan added: “That’s why it’s important to bolster those forces within the Syrian opposition that are not extremists.”
The US military is funding the training and arming of “moderate” Syrian rebel forces but the effort is only now getting off the ground.
Washington’s stance is that Assad should have no role in Syria’s future but President Barack Obama’s administration and other governments wanted to see a political solution that would ensure a representative government, he said.
“None of us, Russia, the United States, coalition, and regional states, wants to see a collapse of the government and political institutions in Damascus,” Brennan said.
The international community favored an eventual settlement that would bring a “representative government that is going to try to address the grievances that exist throughout the country.”
Brennan, who worked for years at the spy agency before he became a top counter-terrorism adviser to Obama, took over as the head of the Central Intelligence Agency in March 2013