U.N.-Arab League envoy Kofi Annan meets with representatives of the Syrian National Council in Ankara.
The SNC is an umbrella opposition group whose leadership lives abroad, and has said it is preparing to arm anti-government rebels.
The meeting follows weekend talks between Annan and beleaguered Syrian President Bashar al-Assad.
Annan later said he expects to hear "concrete proposals" from the Syrian government to end nearly a year of violence.
On Monday, he said the world must send a clear message that the killing of civilians in Syria is "simply unacceptable".
He is also pushing for the establishment of a humanitarian corridor to help those caught up in the violence.
Speaking near the Syrian border in Turkey, a Syrian Free Army spokesman believes Assad will meet the same fate as Libya's despotic former ruler.
(SOUNDBITE) (Arabic) SYRIAN FREE ARMY SPOKESPERSON, AMMAR AL WAWI, SAYING:
"We know that Assad's end will be like that of the Libyan leader Gaddafi because Gaddafi killed the people in his own country, killed the children, raped the women. We, like everyone else, know what Bashar al-Assad is like."
The U.N. estimates Syrian security forces have killed over 8,000 people since the popular uprising began one year ago.
For its part, Syria claims that "armed terrorists" have killed more than 2,000 soldiers and police.
Nick Rowlands, Reuters.