President Vladimir Putin said on Tuesday that Russian Federation had information that the United States was planning to launch new missile strikes on Syria, and that there were plans to fake chemicals weapons attacks there.
Washington responded to a chemical attack last week that killed dozens, including many children, with a missile strike against an Assad air base.
He says Trump's missile strike was meant as a "very strong signal to Assad and his sponsors" that the US will not stand idly by, and that Russian Federation should now reconsider support for the "murderous regime".
The US stepped up the pressure on Sunday on Russian Federation to rein in the Syrian government, warning that any further chemical attacks would be "very damaging" to their relationship and suggesting any peace deal would be hard with Assad in power.
Another U.S. official cautioned that no final American determination has been made that Russian Federation knew ahead of time that chemical weapons would be used.
USA secretary of state Rex Tillerson will go ahead with his visit this week to deliver a "clear and co-ordinated" message to the Kremlin. Under President Barack Obama, the United States accused Russian Federation of supporting Assad in war crimes against civilians and of employing a sophisticated disinformation campaign to protect its ally.
G7 foreign ministers were to send a "clear and coordinated message" to Russian Federation over its stance on Syria as the United States ratcheted up the pressure following a suspected chemical attack in the war-torn country.
"It is the right moment to talk about this, how the worldwide community, with Russia, Iran, Saudi Arabia, Europe, with the US, can drive forward a peace process for Syria and avoid further military escalation of the conflict".
On Monday, Col. John J. Thomas, a US military spokesman, said the USA has taken extra defensive precautions in Syria in case of possible retaliation against American forces for the cruise missile attack.More news: Don't Panic, File a Tax Extension to Buy More Time
G7 efforts to build a united front against Assad comes just ahead of Tillerson's trip to Moscow, the first for a high-ranking Trump administration official.
"I will be meeting with senior members of the coalition again in the coming weeks and we will expect to discuss these activities further", she said.
Assad's government has denied any involvement in the attack in the town of Khan Sheikhoun in the rebel-held Idlib province.
"It reminds me of the events in 2003 when USA envoys to the Security Council were demonstrating what they said were chemical weapons found in Iraq", Putin told reporters Tuesday, according to a translation by The Associated Press.
Mattis ensured Americans that the U.S.'s endgame in Syria - defeating ISIS - remains the same.
Secretary of State Rex Tillerson said there could be "no doubt" that Assad's troops carried out the attack, and autopsies have showed that sarin gas was used.
"Well this is part of the problem in Syria, is Russia's sponsorship of this murderous regime", McMaster said on "Fox News Sunday".
Exasperated, Putin told reporters that that the story is "very tedious".