Syria on Friday slammed Washington’s claims that it had used chemical weapons in its fight against militant opposition groups, accusing the United States of "lies" based on "fabricated information".

Syria on Friday slammed Washington's claims that it had used chemical weapons in its fight against militant opposition groups, accusing the United States of "lies" based on "fabricated information".

"The White House published a statement full of lies about the use of chemical weapons in Syria, based on fabricated information, through which it is trying to hold the Syrian government responsible for such use," state news agency SANA quoted a foreign ministry official as saying.

The official said the US claims came "after reports affirming that armed terrorist groups active in Syria are in possession of deadly chemical weapons and the technology necessary to make them".

Washington said on Thursday there was evidence that the Syrian government had used chemical weapons including sarin nerve gas in its military operations.

The US administration announced it will provide "military support" to the terrorist groups active over the Syrian territories, a decision condemned Moscow, Berlin and Damascus.

"The American decision to arm armed terrorist groups demonstrates... the direct involvement of the United States in the Syrian bloodbath," the official stressed.

"This raises serious questions about their good intention when it comes to finding a political solution in Syria," the official added.

Washington and Moscow have been spearheading efforts to organize a conference in Geneva to find a political solution to the Syrian conflict. However, the US decision to provide Syrian opposition with arms will probably hinder any possible peace efforts.

Syria was hit by a violent unrest since mid-March 2011, where the Syrian government accuses foreign actors of orchestrating the conflict, by supporting the militant opposition groups with arms and money.