Syrian President Bashar al-Assad denounced the opposition as "slaves" of the West in a rare speech on Sunday and called for a national dialogue conference to be followed by a referendum on a national charter and parliamentary elections.

Outlining a reconciliation plan aimed at resolving Syria's 21-month conflict that according to the UN has claimed more than 60,000 lives, Assad called on foreign powers to end their support for rebels seeking to topple his government.

"Regional and international countries must stop funding the armed men to allow those displaced to return to their homes," Assad said to wild applause from crowds packed into the Dar al-Assad Centre for Culture and Arts in Damascus.

"Right after that our military operations will cease," he said, adding without elaborating that a mechanism to monitor such a truce would be established.

Describing the Western-backed opposition as "slaves" of foreign powers, he admitted that Syria was in the throes of a "real war".

The government would soon spell out details of the transition plan, he said, while stressing that any resolution must be purely Syrian and ratified by referendum, including a charter drafted at the national dialogue conference.

After the referendum, new parliamentary polls would be held, followed by the creation of a new government, said Assad.

But he stressed for all this to happen "there must be agreement at the national dialogue conference".

"Just because we have not found a partner, it does not mean we are not interested in a political solution, but that we did not find a partner," he told the audience.

He said the conflict was not one between the government and the opposition but between the "nation and its enemies".

"The one thing that is sure that those who we face today are those who carry the al-Qaida ideology," Assad said, repeating previous assertions that "foreign terrorists" are behind the uprising in his country.

"There are those who seek to partition Syria and weaken it," he said.

But Syria's opposition rejected Assad's peace initiative, saying it was aimed at wrecking diplomatic efforts to end the civil war.

"Assad simply wanted, with the initiative he proposed, to cut the road to reaching a political solution that may result from the forthcoming American-Russian meeting with (UN mediator Lakhdar) Brahimi, which the opposition would not accept unless he and his regime leave," National Coalition spokesman Walid Bunni said.

Bashar al-Assad must step down in order to bring about a political solution to the war in his country, the European Union's foreign policy chief said on Sunday.