BEIRUT (AP) -- Syria said Monday it is prepared to hold talks with armed rebels bent on overthrowing President Bashar Assad, the clearest signal yet that the regime is growing increasingly nervous about its long-term prospects to hold onto power as opposition fighters make slow but persistent headway in the civil war.
Meanwhile, the umbrella group for Syrian opposition parties said it had reversed a decision to boycott a conference in Rome being held to help drum up financial and political support for the opposition. Walid al-Bunni, a spokesman for the Syrian National Coalition, said the move came after a phone call between the group's leader, Mouaz al-Khatib, and U.S. Secretary of State John Kerry.
Al-Bunni told pan-Arab broadcaster Al-Arabiya the decision was made based on guarantees al-Khatib heard from Western diplomats that the conference would be different this time. He did not elaborate. The boycott had put the group at odds with its international backers.
The Syrian talks offer, made by Foreign Minister Walid al-Moallem during a visit to Moscow, came hours before residents of Damascus and state-run TV reported a huge explosion and a series of smaller blasts in the capital, followed by heavy gunfire.
State-run news agency SANA said there were multiple casualties from the explosion, which it said was a suicide car bombing. Britain-based activist group the Syrian Observatory for Human Rights said the explosions targeted a checkpoint, adding there were initial reports of at least five regime forces killed and several wounded.
The talks proposal marked the first time that a high-ranking regime official has stated publicly that Damascus would be willing to meet with the armed opposition. But al-Moallem did not spell out whether rebels would first have to lay down their weapons before negotiations could begin - a crucial sticking point in the past.
The regime's offer is unlikely to lead to talks. The rebels battling the Syrian military have vowed to stop at nothing less than Assad's downfall and are unlikely to agree to sit down with a leader they accuse of mass atrocities.
But the timing of the proposal suggests the regime is warming to the idea of a settlement as it struggles to hold territory and claw back ground it has lost to the rebels in the nearly 2-year-old conflict.
Opposition fighters have scored several tactical victories in recent weeks, capturing the nation's largest hydroelectric dam and overtaking air bases in the northeast. In Damascus, they have advanced from their strongholds in the suburbs into neighborhoods in the northeast and southern rim of the capital, while peppering the center of the city with mortar rounds for days.
Monday night's explosion struck about 800 meters (yards) from Abbasid Square, a landmark plaza in central Damascus. It was followed by several other smaller blasts thought to be mortar shells landing in various districts of the capital. The explosions and subsequent gunfire caused panic among residents who hid in their apartments.
On Thursday, a car bomb near the ruling Baath Party headquarters in Damascus killed at least 53 people, according to state media.
While the momentum appears to be shifting in the rebels' direction, the regime's grip on Damascus remains firm, and Assad's fall is far from imminent.
Still, Monday's offer to negotiate with the armed opposition - those whom Assad referred to only in January as "murderous criminals" and refused to talk with - reflects the regime's realization that in the long run, its chances of keeping its grip on power are slim.
Asked about al-Moallem's remarks, U.S. State Department spokesman Patrick Ventrell said the offer of talks was a positive step "in the context of them raining Scuds down on their own civilians." But he expressed caution about the seriousness of the offer.
"I don't know their motivations, other than to say they continue to rain down horrific attacks on their own people," Ventrell told reporters in Washington. "So that speaks pretty loudly and clearly."
If the Assad regime is serious, he said, it should inform the U.N. peace envoy, Lakhdar Brahimi of its readiness for talks. Ventrell said the regime hasn't done that yet.
Andrew Tabler, a fellow at the Washington Institute for Near East Policy, called the offer "a sign of weakness."
"I think everybody knows, including Bashar Assad, that they (the regime) can't hang onto the whole country," Tabler said.
Mustafa Alani, an analyst with the Gulf Research Center in Geneva, said the regime has "reached the conclusion that they are heading toward a major defeat eventually, and this is the right time to negotiate."