Konashenkov said Friday that Britain was "directly involved in the provocation", but didn't elaborate or provide evidence.
"We have a very high confidence that Syria was responsible and, once again, Russia's failure to stop them and their continued (lack of action) on this front has been part of the problem", White House spokeswoman Sarah Sanders said. She said of the alleged chemical attack that "Russia can complain all it wants about fake news, but no one is buying its lies and its cover-ups".
"All nations and all people will be harmed if we allow Assad to normalize the use of chemical weapons", she said.
Russian Ambassador to the United Nations Vassily Nebenzia (L) and Bolivia's Ambassador to the United Nations Sacha Sergio Llorenty Soliz speak to the media outside Security Council chambers at the U.N. headquarters in NY, U.S., April 12, 2018. "We can not take such risks", he said at a forum.
"The US - the possessor of the biggest arsenal of chemical weapons - has no moral right to blame other countries".
"We are continuing to assess intelligence and are engaged in conversations with our partners and allies", it said.
Since Saturday, when images of ashen toddlers struggling for breath emerged after the alleged attack, there has been a sustained military buildup in the eastern Mediterranean.
Speaking to reporters in Moscow, Lavrov reiterated a strong warning to the West against military action in Syria.
He noted that Russian and US militaries have a hotline to prevent incidents, adding that it's not clear if it would be sufficient amid mounting tensions.
The Russian defence ministry said today that none of the Western strikes in Syria had hit areas covered by Russia's air defences around its air base and naval facility.
A fact-finding mission from the Organization for the Prohibition of Chemical Weapons is expected to head to Douma, the site of the suspected attack. Both the Syrian and Russian governments have said they would support the study. It also said Russian officers found no patients with chemical attack symptoms at a local hospital, and no indication of any burials having taken place of the victims.
He said the attack was staged on April 7 to coincide with military action by Syrian government forces, after the rebel group Jaish al-Islam that long controlled Eastern Ghouta carried out shelling of Damascus from April 3 to 6.
The capture of Douma from rebels who evacuated this week has clinched a major victory for Assad, crushing what was once a center of the insurgency near Damascus, and underlines his seemingly unassailable position in the war.