Washington, Apr26 (IANS/RIA Novosti): US Secretary of Defense Chuck Hagel has said that America has determined that chemical weapons have been used in the civil war in Syria.

Speaking in Abu Dhabi during his first trip as defense secretary to the Middle East, Hagel said the US intelligence community has determined with "varying degrees of confidence" that Syrian President Bashar al-Assad's forces have used the nerve agent sarin on a "small scale" against civilians and rebel forces fighting to oust the regime.

Hagel said "it violates every convention of warfare".

Hagel's comments are the first US confirmation of chemical weapons being used in Syria.

US President Barack Obama has said that the use of chemical weapons in the Syrian conflict would be a "game-changer" that could push the US to intervene in the civil war in Syria, which in just over two years has claimed at least 70,000 lives and displaced millions.

A letter sent to US Senators John McCain and Carl Levin by the director of the White House's Office of Legislative Affairs confirmed that US intelligence has assessed that the "Syrian regime has used chemical weapons on a small scale in Syria".

The letter added, however, that the US has "an obligation to fully investigate" evidence that chemical weapons were used, and was pressing for a UN probe in Syria.