Regime change in Syria could plunge the region into "total chaos," a Kremlin spokesman warned Friday, a day after media reports that dozens of US diplomatic staff members had called for military strikes against Syrian President Bashar al-Assad.
It was the latest sign of growing tensions between Moscow and Washington. The news comes on top of reported Russian airstrikes against a US-backed Syrian rebel force that has focused on fighting Islamic State.
"Liquidating a regime will hardly facilitate successful progress in the fight against terrorism. It can make the region plunge (into) total chaos," Dmitry Peskov, a Kremlin spokesman, told reporters according to the Itar Tass news agency.
"The most important thing is to prevent possible collapse in the country. But, if things go on like they are doing now, collapse will be inevitable and this will be the worst scenario," Russian President Vladimir Putin said.
The comments seemed to be in response to a "dissent channel cable" signed by 51 State Department officers in which they advise a Syria policy of military strikes against al-Assad's government, the Wall Street Journal and The New York Times reported.
The diplomats argued that the current policy in Syria, focused on defeating Islamic State, was benefiting al-Assad.
US State Department spokesman John Kirby on Friday confirmed there was a "dissent channel message" whose principle topic was Syria.
While not discussing the message's content, Kirby reiterated that the administration remained focused on a political solution in Syria. He also acknowledged that it was "unusual" for such a message to have so many signatories.
White House spokeswoman Jennifer Friedman said that the administration welcomed "a strong deliberation on the foreign policy challenges that face our nation" and was "always open to new and different ideas when it comes to the challenges in Syria."
Some US State Department officials are known to differ with President Barack Obama, who has steered clear of direct military intervention against al-Assad, while granting various types of support to some rebel groups.
US officials admit al-Assad is stronger than he was a year ago, largely thanks to Russian air power backing his forces on the ground.
Earlier, US broadcaster CNN quoted US officials saying Russian planes carried out airstrikes on Thursday near the Iraqi and Jordanian border against the New Syrian Army (NSA).
The rebel group is based near the al-Tanf border crossing, which it seized from Islamic State.
The Britain-based Syrian Observatory for Human Rights said the planes carried out two strikes, one that hit inside the NSA camp and the other at its outskirts. Two soldiers were killedand four were injured.
The NSA, backed by the US and trained by Jordan, was designed as a force to combat the Islamic State extremist group. It comprises rebel fighters, many hailing from the Free Syrian Army, the main moderate force that is battling al-Assad.
The Wall Street Journal said the cable calling for a tougher line against al-Assad, five years into the civil war, came "in light of the near collapse of the ceasefire brokered earlier this year."
Russia and the United States have been pushing for ceasefires and brokering deals on the ground since February, though Russia is accused of breaching the cessation of hostilities a number of times by launching airstrikes against rebel positions.
Meanwhile, a humanitarian aid convoy was able to reach the besieged al-Waer area in Homs province, central Syria, a UN official confirmed, saying the area has 37,500 residents.
A second convoy is planned in the coming days, pending government approval, according to the official.
Despite the near total collapse of the ceasefire one advantage of the US-Russia-brokered deals has been increased aid deliveries to vulnerable areas.