According to Press TV, their threats on Friday came as terrorist groups continued shelling a safe corridor declared by the Syrian government for civilians to leave Eastern Ghouta.
Takfiri terrorists have turned the enclave on the suburbs of Damascus to a launch pad for mortar attacks on the Syrian capital.
The Syrian army is currently in the midst of an operation to drive the terrorists out of Eastern Ghouta, but it is facing a hostile West threatening attacks on Syrian troops which it accuses of targeting civilians.
Western leaders were quick to point the finger at the Syrian government after reports of chlorine release in Eastern Ghouta last week.
For years, foreign-backed terrorists have appeared to release chemical substances in the areas close to the site of government airstrikes and capture the aftermath on videos.
French President Emmanuel Macron and his US counterpart Donald Trump vowed there would be “no impunity” in the event of further chemical weapons use in Syria in a telephone call Friday.
Macron “stressed there will be a firm response in the case of proven use of chemical weapons leading to the death of civilians, in close coordination with our American allies,” a statement from the French presidency said.
“France and the United States will not tolerate impunity,” the statement said, adding the leaders also urged Russia to put “maximum pressure” on Damascus to commit to a UN ceasefire across Syria.
Syria and Russia have already declared a unilateral ceasefire across Syria, but that does not include areas held by Daesh, al-Qaeda and al-Nusra Front along with “individuals, groups, undertakings and entities” associated with the terrorist groups.
France has repeatedly warned that evidence of further use of chemical weapons in Syria is a “red line” that would prompt French strikes.
Washington has asked the UN Security Council to set up a new inquiry on chemical weapons attacks, for which the Syrian government has repeatedly denied responsibility.
The United Nations Human Rights Council on Friday was set to hold an emergency session on Eastern Ghouta at the request of Britain.
However, they are generally silent on daily mortar attacks on Damascus, which take the lives of civilians.