The Friends of Syria, a group of 11 countries including Middle Eastern and Western countries, met in London Tuesday to figure out a way to end the brutal civil war.
Syrian opposition leaders were urged to join an international peace conference in Geneva, by foreign ministers from the United States, Britain, France, Turkey and key Gulf states.
Opposition: Assad must go
"We are clear that Syrian President Assad has no role in a peaceful and democratic Syria," British Foreign Secretary William Hague said after the meeting.
US Secretary of State John Kerry met with Ahmad al-Jarba, the head of the Syrian National Coalition, a key coalition group opposed to Assad's government, ahead of the Friends of Syria meeting.
Jarba insisted, "Geneva cannot succeed and we cannot take part if it allows Assad to gain more time to spill the blood of our people while the world looks on."
Last week, the largest faction within the SNC said it would not take part in talks if Assad remained in power.
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The Syrian president might have something to say on that: "Personally, I don't see any obstacles to being nominated to run in the next presidential elections," Bashar al-Assad said in an interview aired on Monday.
On the Geneva peace conference, Assad said, "There is no date so far ... and current factors do not help in holding it."
Arab League chief Nabil al-Arabi said Sunday the so-called Geneva 2 talks would be held November 23.
The SNC is expected to decide by November 1 whether it will attend the peace conference at Geneva.
Increasing sectarianism, extremism
The increasing power of radical Islamist groups on the Syrian battlefield has complicated efforts to arm the moderate opposition or direct aid, according to officials cited by the Associated Press.
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Earlier in October, 65 rebel groups, including some extremist groups and some affiliated with the moderate Free Syrian Army, said they would no longer recognize the authority of the Western-backed SNC.
Talks in Geneva to end the Syrian civil war have been delayed numerous times. Whether or not Assad should take part in the peace talks remains a sticking point on whether groups come to the table in Switzerland.
Mission to destroy chemical weapons
Meanwhile, the Syrian government has "fully cooperated" with international chemical weapons inspectors destroying its stockpile of chemical weapons, according to the chief of the joint Organization for the Prohibition of Chemical Weapons and United Nations mission.
"To date, the government of Syria has fully cooperated in supporting the work of the advance team and the OPCW-UN joint mission," said mission chief Sigrid Kaag on Monday.
The mission is carrying out work outlined by a UN-backed deal brokered by the United States and Russia, which would see Syria's chemical weapons stockpiles destroyed by mid-2014.