Russia has been sharply criticised by other world powers at the UN Security Council in New York over the chemical weapons deaths in northern Syria, the BBC said.
It added that Moscow’s suggestions that civilians were poisoned by rebel weapons on the ground have been widely rejected.
The UK’s foreign secretary, a rebel commander and a weapons expert all said evidence pointed to an attack by the Syrian government, Russia’s ally, the BBC reported.
International donors have pledged $6bn (£4.8bn) in aid for Syria this year, according to the BBC.
Seventy donor nations discussed aid efforts in the war-ravaged country in the Belgian capital, Brussels, it also said.