France's foreign minister says President Bashar al Assad has "won the war" in Syria, but warned that he could not achieve lasting peace without a negotiated settlement.
He added: "The Russians and Iranians would be making a grave humanitarian mistake to take part in this potential human tragedy".
The Kremlin said they would discuss further measures "aimed at finally liquidating the hotbed of global terrorism" in Syria, where the conflict has killed more than 350,000 people since 2011. "Don't let that happen!"
In the case of Idlib, an estimated 10,000 fighters with the Al-Qaeda-linked Hayat Tahrir al-Sham group are believed to be the dominant force among rebels in the province, and the Russian military has made a distinction between those forces and what it has described as more moderate "opposition" groups allied with Turkey, its negotiating partner.
The Syrian army gears up for a major offensive to retake the last terrorist stronghold, but it is facing threats of being hit by the USA and its allies if a chemical attack takes place in the province.
However, the London-based watchdog said the rebel attack against the government positions in Latakia was not carried out by drones but through artillery shelling.
"There is no doubt that the issue should be dealt with", Peskov said. "We do know that the Syrian armed forces are getting ready for tackling this problem".
In recent months, the Syrian army has managed to liberate numerous areas occupied by terrorists and is preparing to launch an attack to recapture the northern city of Idlib.
On Saturday, U.S. Secretary of State Mike Pompeo said that Washington views any government assault on Idlib as an escalation of Syria's war, and warned that Washington would respond to any chemical attack by Damascus.
The rise in tensions comes ahead of meetings aimed at creating a commission to help draft a new Syrian constitution.
The Iranian Foreign Ministry on Monday labeled an upcoming trilateral summit between Iran, Russia and Turkey on Syria as a "step toward peace, security and stability" in the war-torn country. A few days later Mistura will meet with envoys from the U.S., U.K., France, Saudi Arabia, Jordan, Germany and Egypt.
Mistura, in Geneva, echoed Trump's call for calm, saying violence could "hold hostage" efforts at a political settlement.
The Pentagon responded Friday, saying, "Russia has recently launched a concentrated disinformation campaign to discredit the United States and global partners and allies" and calling Lavrov's allegation about preparations for a staged chemical strike "absurd".
Javad Zarif visited Turkey last week and met President Recep Tayyip Erdogan, who has been a staunch supporter of Syria's rebel forces against Assad.
A $1 billion covert program run by the Central Intelligence Agency was more successful, but was decimated by Russian bombing and cancelled in mid-2017 by the Trump administration.