DAMASCUS: Pressure mounted Tuesday on Syrian President Bashar al Assad to respond to a surprise offer of talks by his main political opponents aimed at ending warfare in which tens of thousands of people have died.

Assad himself has yet to comment on the offer from Ahmed Moaz al-Khatib, leader of Syria's opposition National Coalition, but pro-regime Al-Watan newspaper described it as a political “manoeuvre” that comes two years too late.

Khatib told pan-Arab television channel Al-Jazeera on Monday that “the ball is now in the regime's court. They will either say yes or no.”

He was following up on his surprise announcement last week that he was ready for talks with the Damascus regime – subject to conditions, including the release of 160,000 detainees – on ways to end the conflict that has ravaged Syria since March 2011.

He later elaborated, telling Al-Arabiya news channel he was ready to meet Assad's deputy, Vice President Faruq al-Sharaa.

In the past the opposition has demanded Assad step down before talks can begin but analysts say Khatib's change in stance stems from a belief that the population will be bled dry while the West fails to act.

Experts have also predicted that Khatib's overture will be rejected outright by Damascus, with Assad unlikely to accept his conditions for talks.

Giving hint of what is likely to be an official reaction to the proposal, Al-Watan said Tuesday that Khatib's offer came too late.

“Despite their importance, the statements of Sheikh Moaz al-Khatib are two years late. During that time, our finest young men have died, suffered wounds or been exiled, while we have lost our electricity and fuel infrastructure, alongside several military positions,” it said in a long editorial.

“So the ball is not in the Syrian state's hands, as Khatib said,” Al-Watan added.

Washington gave strong backing to Khatib's call for dialogue.

US State Department spokeswoman Victoria Nuland said that if the Syrian regime is interested in peace “it should sit down and talk now with the ... Coalition, and we would strongly support al-Khatib in that call.”

But she stressed that the US position remained unchanged on bringing to account those, on both sides, who have committed atrocities.

Assad last month announced he was ready for talks with the opposition but ruled out meeting groups such as Khatib's National Coalition, which backs rebels seeking to overthrow his regime.

Some opponents of Assad's regime denounced Khatib's offer for talks, while others welcomed it.

“To negotiate is difficult. They may be doomed and they may fail, but the attempt to stop the bloodbath with a proposal so humane may reap more fruits than merely waiting,” prominent Kurdish activist Massoud Akko said on his Facebook page.

Meanwhile, Hadi al-Abdallah, an activist in besieged Quseir in the central province of Homs, told AFP via the Internet he considered Khatib's proposal naive.

“We are not against the idea of negotiations per se. But we reject completely the idea of negotiating with this regime, which on previous occasions has taken advantage of opportunities for peace to gain time while it simply continued killing,” Abdallah said.

Another activist Abu Nadim, speaking via Skype from Damascus province, said: “We trust Khatib as a person. But in politics, we here feel that good intentions are not enough.

“Everyone wants Khatib's wish to come true. But will it happen?”

Fresh violence meanwhile erupted Tuesday in the northern city of Aleppo where rebels clashed with troops near an army barracks, the Syrian Observatory for Human Rights said.

Army tanks also shelled the districts of Qadam and Assali on the outer edges of Damascus, the Britain-based watchdog added.

Tuesday's violence came a day after at least 123 people were killed in violence across Syria.

The United Nations says more than 60,000 people have been killed in violence across Syria since the outbreak of a revolt in March 2011 that morphed into an insurgency after the army launched a brutal crackdown on dissent.