JERUSALEM » President Barack Obama said today that the United States is investigating whether chemical weapons have been deployed in Syria, but he’s “deeply skeptical” of claims by Syrian President Bashar Assad’s regime that rebel forces were behind such an attack.

Both the Assad regime and Syrian rebels have accused each other of using chemical weapons in an attack on Tuesday. Obama said anyone familiar with the facts of the chemical weapons stockpile in Syria would question the government’s claim that it was the rebels who carried out such an attack.

“Once we establish the facts, I have made clear that the use of chemical weapons is a game changer,” Obama said in a news conference with Israeli Prime Minister Benjamin Netanyahu. Obama said he wouldn’t announce what the next steps would be while the investigation is unfolding. But he echoed up his statement over the summer that the use of chemical weapons in Syria would be a “red line” for the United States.

“When you start seeing weapons that can cause potential devastation and mass casualties and you let that genie out of the bottle, then you are looking at potentially even more horrific scenes than we’ve already seen in Syria. And the international community has to act on that information,” Obama said.

Obama says the U.S. policy not to intervene militarily or arm Syrian rebels thus far is based on his desire to solve the problem as a global community. “It’s a world problem when tens of thousands of people are being slaughtered, including innocent women and children,” Obama said.