“As we warned a few days ago, a media propaganda campaign on the ‘use of chemical weapons by Damascus’ has begun,”Zakharova wrote on Facebook, RT reported.

Zakharova’s post was accompanied by a screenshot from a video being shared on social media allegedly showing a hospital in Eastern Ghouta. The speaker in the video claims the people he is filming have been affected by “chlorine gas used by the regime.”

“There will be more of such videos, and they will be of different quality – either low-grade, like this one or of Hollywood level. There will be many fakes, the planned campaign is a massive one,” the Foreign Ministry Spokeswoman said.

A militant group on Saturday accused government forces of using chlorine gas against its fighters East of Damascus.

Meanwhile, the General Command of the Syrian Armed Forces stressed that claims made by some terrorist-affiliated websites about the Syrian Army's using of chlorine gas against militants of Faylaq al-Rahman in Ein Terma region in Eastern Damascus are false and baseless.

The Spokesperson for the United States administration had accused Syria of preparing to stage a chemical attack in the country, threatening that Washington would make Damascus pay “a heavy price.”

The Iranian foreign ministry warned that any US aggression against Syria will further deteriorate the security situation in the region and help the terrorists.

"While the Syrian government has been fighting against terrorism and terrorist groups with all its power and resources for 6 years now and has paid a heavy price to this end, raising such unfounded allegations and adopting measures which will yield no result but strengthening the terrorist groups' status and situation and further complicating the fight and confrontation against these groups is highly questionable and suspicious," Foreign Ministry Spokesman Bahram Qassemi said in reaction to the recent US threats against Syria.

He reminded the US illegal aggression against Syria's al-Shayrat airbase under the pretext of an alleged chemical weapons use by Damascus, and said Iran and Russia had called for sending an international fact-finding delegation to study Washington's allegations but the US blocked the move.

Qassemi called on the international community to show proper and deterrent reaction against such unilateral and illegal moves.

Russian Ministry of Foreign Affairs said in a statement that Moscow perceives allegations made by the White House that Syria could be preparing a chemical attack as an "invitation" for terrorists to launch a provocation using chemical weapons.

"We consider these new insinuations on the issue of weapons of mass destruction — in the worst traditions of 2003 NATO intervention in Iraq — to be nothing less than an invitation for terrorists, extremists and armed opposition in Syria to fabricate another mass provocation using chemical weapons," the statement, published on the Ministry's website, said.

"After (the provocation), the 'inevitable punishment' for the Syrian President Bashar al-Assad should follow, as envisioned by Washington," it added.

The Kremlin also commented on the White House's claim on Tuesday and stressed that it considers US' threats against Syrian legitimate leadership to be "unacceptable."

Kremlin Spokesperson Dmitry Peskov pointed out that the Syrian government cannot be held accountable for the April 4 chemical attack in the Idlib province "because, as you know, despite all of Russia's demands, an unbiased international investigation of the previous tragedy has not been carried out."

Damascus also denied the allegation, as Ali Haidar, the Minister of State for National Reconciliation Affairs in Syria, said that Damascus "never used and will never use such weapons," adding that the statement issued by the White House portends a "diplomatic battle" against Syria in the UN.

As Washington claims that it fights against the ISIS group, US warships fired 59 Tomahawk cruise missiles from two warships in the Mediterranean Sea at the Shayrat airfield in Homs province on April 7, following a chemical weapons incident in Idlib province on April 4 which the Western countries blamed on the Damascus government.

The Syrian government has fiercely denied using or even possessing chemical weapons since the country’s compliance with the Chemical Weapons Convention was certified by international observers in 2013, as the world is still waiting for the US and its allies to provide any proof for its claims of Bashar al-Assad government involvement in the alleged chemical attack.

The Syrian President had characterized the alleged chemical attack in Khan Sheikhoun as a provocation to justify the US strike on Shayrat airbase in Homs province. The Syrian leader also warned of the possibility of the new provocations similar to the one in Idlib.