Tel Aviv, Mar 21 (IANS/RIA Novosti): US President Barack Obama said Wednesday he was "deeply skeptical" of Syrian government claims that its opponents used chemical weapons in the civil conflict there.

He warned any use of such arms would be a fundamental "game changer" in the world's action on the crisis.

"I am deeply skeptical of any claim that in fact it was the opposition that used chemical weapons," Obama told journalists in Jerusalem at a joint news conference with Israeli Prime Minister Benjamin Netanyahu.

"Anyone who knows the facts of the chemical weapons stockpiles inside of Syria, as well as the Syrian government capabilities, I think would question those claims," Obama said.

His comments came a day after the Syrian government and opposition rebels each accused the other of having used chemical arms during fighting in the northern Syrian city of Aleppo.

Shortly before Obama spoke, the US ambassador to Syria, Robert Ford, told a congressional panel that "so far we have no evidence to substantiate those reports" on use of chemical weapons.