Syrian regime forces
Syrian regime forcesReuters

Talks in Switzerland between Washington, Moscow and Syria's neighbors ended within hours of starting on Saturday with no breakthrough on halting the violence ravaging the war-torn country.

U.S. Secretary of State John Kerry said the Lausanne meeting produced some new ideas on reviving a ceasefire in Syria, where the regime continues to pound rebel-held areas in Aleppo.

But he also added it was too early to reveal what these ideas were, and that high-level contacts -- but not a ministerial-level meeting -- would continue on Monday to flesh them out.

Kerry welcomed what he said had been more than four hours of "very candid, first time discussion ... open and free-wheeling ... with all of the key parties at the table simultaneously."

"I would characterize this as exactly what we wanted," he told reporters at the lakeside hotel where he met Russian, Iranian, Saudi, Turkish, Egyptian, Jordanian, Iraqi and Qatari envoys.

Kerry's tone was upbeat, but came despite diplomats from all sides warning against hopes of a rapid ceasefire.

And away from the talks, Moscow's actions showed no sign that it might be softening its strong support for Syrian President Bashar Al-Assad and his campaign against U.S.-backed rebels.

Fierce fighting was also continuing elsewhere in the multi-front conflict, with Turkish-backed fighters closing in on Dabiq, a symbolic stronghold of the Islamic State (ISIS) group.

Meanwhile in Aleppo, Assad's Russian-backed government forces intensified their bombardment of the rebel-held east of the city, further damaging any prospect of a renewed ceasefire.

The Syrian army announced an all-out offensive against the rebel-controlled section of Aleppo on September 22, shortly after a previous ceasefire brokered by the United States and Russia fell apart.

Kerry and Russian counterpart Sergei Lavrov, once joint sponsors of international peace efforts, met ahead of the broader talks, but U.S. officials insisted that their "bilateral track" remained dead.

Lavrov joined Kerry in welcoming the idea of bringing other powers into the mix saying, "we must prolong our contacts over the coming days".

President Barack Obama has been adamant that American forces will not become caught up in the war and Kerry was hoping that talks with Russia and regional powers may yield new ideas.

Kerry said that the group -- bigger than bilateral U.S.-Russian talks, but small than the 23-nation International Syria Support Group -- had proved diplomatically productive.

While there were tensions he said, they shared the goal of a reduction in violence, more humanitarian access to besieged areas and a very quick return to political dialogue.

"The way it wrapped up was to have several ideas that need to be quickly followed up," Kerry said.

"The next contact on trying to follow up on this is going to be immediately, because this is urgent, and we're not letting any grass grow under our feet," he added.

The talks come as Moscow faces growing criticism over its backing for Assad's assault in divided Aleppo.

Air strikes hit rebel-held parts of Aleppo again Saturday, according to the Syrian Observatory for Human Rights, a British-based watchdog with a network of sources on the ground.

This past Tuesday, at least 12 civilians were killed in the heaviest Russian bombardment in days of Aleppo.

The intensified bombardment has put even further strain on rescue workers in besieged eastern Aleppo which is home to an estimated 250,000 residents.

More than 370 people, including nearly 70 children, have been killed in regime and Russian bombardment of eastern Aleppo since September 22, according to the Observatory.

AFP contributed to this report.