On the ground in Syria meanwhile President Bashar al-Assad's forces made a breakthrough, entering two Shiite villages that had been under siege by rebels after also advancing around the second city Aleppo.
Syria's state news agency SANA reported "mass celebrations" in the streets of Nubol and Zahraa as people welcomed army troops and celebrated the breaking of the siege.
Peace talks in Geneva were suspended yesterday until February 25, with UN special envoy Staffan de Mistura saying "more work" was needed.
But French French Foreign Minister Laurent Fabius accused Damascus and Russia of "torpedoing the peace efforts" in Geneva with the offensive.
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Russia has been launching air strikes in Syria which it says are targeted at "terrorist organisations" such as the Islamic State group.
Fabius added that world powers would hold "in-depth consultations" on their actions at the aid conference in London.
US Secretary of State John Kerry warned Moscow to halt its bombing of the Syrian opposition in what he said was a "robust" phone call with Russian counterpart Sergei Lavrov.
UN Secretary-General Ban Ki-Moon said the temporary pause in the talks showed "just how deep, how difficult the divisions are."
At the start of the conference in London, co-host British Prime Minister David Cameron urged a political transition away from Assad in Syria "however difficult that may be."
The suspension of the talks came as donors gathered in the British capital aiming to raise billions of dollars in aid for Syria and to help its neighbours cope with millions of people that have taken refuge on their soil.
German Chancellor Angela Merkel, under growing pressure over her open door policy for refugees amid Europe's biggest such crisis since World War II, pledged 2.3 billion euros.
Some 4.6 million Syrians have fled to nearby countries - Jordan, Lebanon, Turkey, Iraq and Egypt - while hundreds of thousands have journeyed to Europe.