Tasnim� Whenever US-backed mercenaries suffer a heavy blow in Syria, Washington resorts to the recurring and fabricated allegation of chemical attacks by Damascus, Iranian official Ali Akbar Velayati said.

In an interview with Tasnim, Velayati -an international adviser to the Leader of the Islamic Revolution- slammed the US allegation that the Syrian government has launched chemical attacks, describing it as a repeated, fabricated propaganda trick that follows the defeat of US-backed militants in Syria.

Frustrated with the failure of their mercenaries in the battlefield, the US and its allies repeat the allegations of use of chemical weapons in Syria, he deplored, saying no one in the world would believe such claims by notorious propagandists like the US anymore.

Velayati also reaffirmed Iran�s commitment to supporting the Syrian nation and its legitimate government, and to strengthening the axis of resistance, including Iran, Iraq, Syria and Lebanon.

His comments came amid reports of a looming US military attack on Syria in response to the alleged use of chemical weapons by Damascus, which the Syrian government vehemently denies.

The Syrian army has put its forces on high alert after the US threat.

The US, France and Britain were in extensive consultations about launching a military strike as early as the end of this week, US officials have said.

The Russian military, which has troops in Syria, said on Monday that its officers had visited the site of the alleged attack and found no evidence to back up reports of poison gas being used.