John Kerry is due to meet European foreign ministers in London to discuss the conflict in Syria, a day after "tense, difficult" talks with Russia ended inconclusively.
The diplomats are to discuss on Sunday the results of the US Secretary of State's meeting on Saturday in Switzerland, which included the foreign ministers of Turkey, Saudi Arabia and Qatar, and how to reduce the violence in Syria.
Several major international efforts have failed to secure a political solution to Syria's civil war, which has cost more than 400,000 lives since 2011.
The meeting in Lausanne did not produce a concrete plan to restore the truce that collapsed last month amid bitter recriminations between the US and Russia and new fighting on the ground.
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But Kerry insisted that the new, leaner contact group had come up with some plausible ideas that would be fleshed out in the coming days and might lead to a new, stronger ceasefire.
"The way it wrapped up was to have several ideas that need to be quickly followed up," he said after talks with Russia, Iran, Iraq, Qatar, Jordan, Saudi Arabia, Egypt and Turkey.
"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."
The flurry of diplomacy comes weeks after a ceasefire deal collapsed and the US suspended cooperation with Russia over its continued bombing of the city of Aleppo.
"I think [Sergey] Lavrov [Russian foreign minister] and Kerry were trying to put a brave face on what happened here," Al Jazeera's Diplomatic Editor James Bays, reporting from Lausanne, said.
"They came to the table again to sort out the situation in northern Syria, particularly the bombardment of Aleppo, and once again diplomacy failed the people of Aleppo.
"No breakthrough, no concrete developments at all from these talks."
Lavrov said after the talks that he had pressed for a "political process" to end the conflict to begin "as soon as possible", while Kerry said they had talked about new ideas for a ceasefire.
While the diplomatic efforts continue, on the ground the fighting shows no signs of abating.
Activists say Russian and Syrian government air strikes killed 11 civilians on Sunday. The strikes hit residential areas and a medicine factory in Idlib and Aleppo provinces.
Before Saturday's talks were due to begin, dozens of overnight air strikes struck east Aleppo, Britain-based Syrian Observatory for Human Rights said on Friday.
Three hospitals in Aleppo were hit by suspected Russian air strikes on Friday, killing seven people, sources told Al Jazeera.
More than 370 people, including nearly 70 children, have been killed in Syrian government and Russian bombardment of east Aleppo since September 22, according to the Syrian Observatory.
Elsewhere in Syria, fighters backed by Turkey have advanced on the northwestern town of Dabiq, which is held by the Islamic State of Iraq and the Levant (ISIL) group, according to the Turkish president.
Speaking in Rize, a city on the Black Sea coast, on Saturday, President Recep Tayyip Erdogan said: "We entered Jarablus, and then al-Rai, and now we are moving where? To Dabiq. We will declare a terror-free safe zone of 5,000 [square] kilometres."
He was referring to areas in Syria already captured by Turkish troops and Turkey-backed opposition forces.
Abdul-Razzaq Freiji, a Turkey-backed Syrian commander, said participants in the Operation Euphrates Shield were bombarding Dabiq and the nearby town of Soran, in preparation for an all-out ground offensive on the two areas.
"Daesh members have gathered lots of fighters for this battle that will be harsh," Freiji told the Associated Press news agency, using the Arabic acronym for ISIL, also known as ISIS.
"We are ready for the battle and we will take it [Dabiq] no matter what the price is, and after that we will march toward another ISIL stronghold] ]al-Bab."
Dabiq is central to ISIL propaganda, with the group citing ancient prophecy declaring the town as the scene of an apocalyptic battle between Christianity and Islam.
The group named its online magazine after Dabiq, which it has occupied since August 2014.
Source: Al Jazeera And Agencies