Syria has said it is prepared to hold talks with armed rebels bent on overthrowing president Bashar Assad.
It is the clearest signal yet that the regime is growing increasingly nervous about its long-term prospects to hold on to 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 US Secretary of State John Kerry.
Mr 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 people in 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. British-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 Mr 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.
An international human rights organisation said the Syrian military fired at least four ballistic missiles into the embattled northern city of Aleppo over the past week, killing more than 140 people, including 70 children. Human Rights Watch said the attacks on residential areas of Aleppo marked an "escalation of unlawful attacks against Syria's civilian population".
A researcher with the US-based group, who visited Aleppo last week to inspect the targeted sites, said up to 20 buildings were destroyed in each area hit by a missile. There were no signs of any military targets in the residential districts, located in rebel-held parts of Aleppo, the group said. Aleppo has seen some of the heaviest fighting in Syria's conflict.