BEIRUT (AP) -- Syria's main opposition bloc wants to consult its allies before deciding on joining a U.S.-Russia initiative to negotiate a peaceful transition in Syria, its leader said Monday.
The U.S. and Russia called last week for an international conference to start talks that would be accompanied by a cease-fire. The two nations are on opposite sides of the Syria conflict, and this marks their first serious joint attempt at Syria diplomacy in a year.
The time, venue and agenda of the conference have not been set, reflecting disagreements between the two warring sides in Syria that scuttled previous initiatives.
Both have agreed in principle to attend, but the opposition Syrian National Coalition says it will not negotiate unless President Bashar Assad steps down first, while the regime has been vague about a truce.
George Sabra, head of the SNC, said Monday his coalition wants to consult with its allies, including Turkey, Saudi Arabia and Qatar, before making a decision.
"It is still early to make a decision on attending the conference," Sabra told reporters in Istanbul, Turkey. "It still has no agenda, program and list of attendees."
Even so, it appears unlikely the largely exile-based SNC would refuse to take part, especially if its regional allies back the conference. U.S. diplomats have met with Arab leaders to ensure the opposition will get on board.
A smaller opposition coalition of 16 groups with roots in Syria will take part in peace talks, its leader, Hassan Abdul-Azim, told the Beirut-based Al-Mayadeen TV on Monday. Speaking from Damascus, he said coalition members were invited by the Russian ambassador to Syria.
The National Coordination Body for Democratic Change in Syria has been tolerated by the regime, though several of its senior figures are in jail. The group has long called for talks on a peaceful transition.
Work on logistics for the conference is underway.
Arab League chief Nabil Elaraby said over the weekend that Syria has given its list of attendees to its ally Russia. There was no immediate Syrian government comment.
Elaraby said the international envoy to Syria, Lakhdar Brahimi, is working on the setting up the conference, but no date has been set. Initially, the U.S. and Russia said it should be held by the end of the month.
The uprising against Assad erupted in March 2011 and escalated into a civil war. More than 70,000 Syrians have been killed and millions displaced.
Western leaders face growing pressure to find a way to end the conflict -- both because of the steadily rising death toll and fears that neighboring Turkey, Lebanon or Israel could get pulled deeper into it.
Turkey has blamed the Assad regime for twin car bombs Saturday that killed 46 people and wounded scores in a Turkish border town that serves as a hub for Syrian refugees and rebels.
Turkish Prime Minister Recep Tayyip Erdogan said Monday that Syria was behind the attacks "with certainty." He said Turkey is not ruling out retaliation but will act with caution and avoid being drawn into the civil war.
Syria has vehemently denied Turkey's accusations. There has been no claim of responsibility for the blasts in the town of Reyhanli.
On another front, Israel attacked suspected shipments of advanced Iranian missiles in Syria with back-to-back airstrikes this month. Israeli officials signaled there would be more attacks unless Syria refrains from trying to deliver such "game-changing" missiles to ally Hezbollah, an anti-Israel militia in Lebanon. Hezbollah responded by saying weapons shipments won't cease.
For now, the West is placing its hopes on the revived U.S.-Russian diplomatic initiative. Similar efforts ran aground in the past but now appear to have stronger Russian backing.
Through the conflict, Russia has sided with Assad, sending him weapons and shielding him against Western attempts to impose international sanctions.
British Prime Minister David Cameron suggested en route to a meeting with President Barack Obama that Russia is ready to find common ground with the West. Cameron met last week with Russian President Vladimir Putin to discuss the Syria initiative.
Cameron said late Sunday that there was a recognition by Putin "that it would be in all our interests to secure a safe and secure Syria with a democratic and pluralist future, and end the regional instability."
In fighting in Syria, regime troops have taken full control of the strategic town of Khirbet Ghazaleh, near the highway linking the capital Damascus with Jordan, according to the Britain-based Syrian Observatory for Human Rights, an activist group.