Russia, one of Syria's strongest backers, has said Moscow cautiously supports calls for Syria to withdraw its troops from Lebanon.
Demonstrations against Syria have been going on for weeks
Russian Foreign Minister Sergei Lavrov said the withdrawal should not violate "the fragile balance" in Lebanon.
Lebanese opposition leaders demanded on Wednesday that Syrian forces withdraw and Lebanese security chiefs resign.
Mr Lavrov said he hoped that elections in Lebanon - following the government's resignation - would take place soon.
He told the BBC's Newsnight programme that a new government would be a stabilising factor, and that the process of withdrawal of Syrian troops would take place.
He added that Lebanon had a complicated power structure and was a very difficult country ethnically and religiously.
Walid Jumblatt, a prominent leader of the Druze sect, announced the opposition's list of demands after hosting a meeting of opposition groups to discuss a common strategy.
Druze leader Jumblatt hosted the opposition talks at his home
They said the moves had to precede any talks with Syrian-backed President Emile Lahoud on forming a government.
The government of Prime Minister Omar Karami resigned on Monday after two weeks of protests over the killing of former Prime Minister Rafik Hariri.
Many Lebanese blame Syria, which has played a strong role in Lebanon's affairs for decades, for the bombing that killed Mr Hariri.
Mr Jumblatt said the opposition considered it "essential" that Syria withdraw its troops and intelligence services from Lebanon - and demanded an official statement from Syrian President Bashar al-Assad.
Mr Jumblatt said the opposition would only take part in discussions on forming a new government after Mr Lahoud accepted the demands.
Some MPs want Mr Lahoud himself to quit, saying he is too close to Syria, which still dominates much of Lebanon.
Popular protests continued in Beirut on Wednesday.
SYRIA IN LEBANON
Military intervention begins in 1976
30,000 troops in Lebanon during 1980s, currently 15,000
Syrian forces crucial in ending the Lebanese civil war in 1990 and maintaining peace
Calls for departure of the Syrians increase gradually with Israeli withdrawal in 2000
UN resolution calling for withdrawal of all foreign forces passed in Sept 2004
But reports said only a few hundred people remained in Martyrs' Square, in contrast with the 25,000 or more who were there on Monday. The rallies have focused on demands for Syria to withdraw its 15,000 troops and to stop other interference in Lebanon.
President Assad told a US magazine that a military pullout could begin "very soon", but Mr Jumblatt and Israeli officials responded with scepticism, saying they wanted action rather than words.
Damascus is also coming under increasing pressure from outside the region, with US President George W Bush leading Western calls for Syria to cut its influence in Lebanon.
The protesters in Beirut have also been calling for an international inquiry into the Hariri killing in a massive car bombing last month.
The body of another victim of the blast was recovered from the debris in central Beirut on Wednesday, 16 days after the attack.