They demanded on Wednesday the "immediate" resignation of Lebanon's public prosecutor and six top security officials to ensure the integrity of the probe into the 14 February assassination of former prime minister Rafiq al-Hariri.
Al-Asad should make an "official announcement" for a complete and "honourable" pullout of Syrian troops and intelligence services from Lebanon, the opposition said in a statement issued after a meeting in the mountain village of Mukhtara.
Key figure Walid Jumblatt, at whose residence some 70 opposition leaders met, said any compromise with Lebanon's Syrian-backed President Emile Lahud would depend on "the dismantling of the security apparatus".
They also said they would not join any talks on new government formation until their demands were met.
The Lebanese opposition figures announced their decision at a media conference after holding a crucial meeting to find a common position on the formation of an interim cabinet following the resignation of pro-Syrian prime minister Umar Karami.
Beirut has been seeing massive
protests since al-Hariri's killing
The opposition intends to participate through a delegation or a single MP in mandatory parliamentary consultations with President Lahud to nominate a new prime minister, participants said.
During the meeting, Jumblatt also demanded that Syria give precise dates for withdrawing its 15,000 troops from Lebanon.
Jumblatt has played a major role in the "Syria Out" campaign.
He has said Lahud should resign but other opposition leaders have said that is not on their agenda.
end of May.
The new government will be in charge of leading the probe into al-Hariri's assassination, negotiating the Syrian redeployment before a complete pullout, and supervising legislative elections due by the
Hizb Allah mediation?
Meanwhile, Lebanon's opposition has asked the head of the Syrian-backed Shia militia Hizb Allah to secure direct dialogue with Damascus to win a Syrian troop pullout.
"We have already said that we wanted direct dialogue with Syria and I think that [Hizb Allah chief] Sayyid Hassan Nasr Allah is well placed to play that role," opposition MP Ghazi Aridi said after meeting with the head of the group.
"We have full confidence in Sayyid Nasr Allah, and through him, we address Syrian officials in order to put an end to all that is happening ... because Syria is responsible, concerned and affected by what is happening in Lebanon," he said.
"We have already said that we wanted direct dialogue with Syria and I think that [Hezbollah chief] Sayyid Hassan Nasr Allah is well placed to play that role"
Hizb Allah, which enjoys wide support from the government, Syria and Iran, was instrumental to the May 2000 Israeli troop withdrawal from southern Lebanon after 22 years of occupation.
In an effort appreciated by all sides, Nasr Allah has repeatedly called for calm and national accord.
"Our only choice is dialogue if we care for Lebanon ... as the internationalisation [of the issue] only complicates things," he recently said.
Walid Sharara, a specialist in Shia affaires, said Hizb Allah is seeking to "play the role of a mediator" between the parties in the dispute.
"This crisis is embarrassing Hizb Allah which feels that a polarisation of political life in Lebanon carries dangers and risks to limit its role as a dissuading force against Israel," he said.
Nasr Allah's Hizb Allah is backed
by Syria and Iran
"A few months ago, Hizb Allah had a free hand in defending southern Lebanon by benefiting from the backing of the state and the Lebanese society," he said.
Al-Hariri's assassination has dealt a severe blow to Hizb Allah which lost a strong ally in the slain billionaire tycoon.
"Al-Hariri was engaged in contacts with his European friends to prevent them from putting Hizb Allah on the list of terrorist organisations," as requested by Israel, said Nasr Allah.