Russia's foreign minister says a suspected chemical attack in the Syrian town of Douma last weekend was fabricated with the help of an unspecified foreign intelligence agency.
Sergei Lavrov said on Friday that Russian experts had inspected the site of the alleged attack in Douma, just east of Damascus, and found no trace of chemical weapons.
He said Moscow had "irrefutable information that it was another fabrication".
Lavrov, speaking to reporters in Moscow, said: "Intelligence agencies of a state that is now striving to spearhead a Russo-phobic campaign were involved in that fabrication."
He did not elaborate or name the state.
The attack has drawn international outrage and prompted the US and its allies to consider a military strike on Syria, something Moscow has strongly warned against.
"God forbid anything adventurous will be done in Syria following the Libyan and Iraqi experience," Lavrov said.
He said even the smallest miscalculation in Syria could lead to new waves of migrants and that ultimatums and threats do not help the dialogue.