Secretary of State John Kerry says chemical weapons were used in Syria and is accusing President Bashar Assad of destroying evidence.

U.S. Secretary of State John Kerry delivers a statement about the use of chemical weapons in Syria at the Department of State (Chip Somodevilla/Getty Images)

Ratcheting up criticism of Syria's alleged chemical weapons use, Kerry called last week's attack a "moral obscenity" that should shock the conscience of the world.

He says the U.S. has additional information about the attack and will make it public in the days ahead.

Kerry says shelling the affected area afterward was not the action of a government trying to cooperate with U.N. investigators trying to assess what happened.

The alleged chemical weapons attack on Aug. 21 that killed hundreds has moved the U.S. closer to military action against Syria than at any point during the bloody civil war.

Syrian President Bashar Assad has denied launching a chemical attack.

Inspectors return to Damascus after visiting hospital

DAMASCUS, Syria (AP) — Activists in Syria say U.N. inspectors have spent about three hours at a makeshift hospital in one of the areas near Damascus that were hit by what the opposition says was a chemical weapons attack by government forces last week.

The inspectors met with doctors and took samples from victims before heading to Damascus.

Earlier today, one of their vehicles was hit by sniper fire. The government says rebel forces were responsible, while the rebels blame a pro-government militia.

The government says its forces provided security for the team until it reached a position controlled by the rebels, where the government says the sniper attack occurred.

A member of the Syrian opposition group in exile says members of a pro-government militia fired at the U.N. team to prevent it from going in. He says five U.N. investigators eventually arrived at the hospital, where doctors and about 100 people still suffering symptoms from the alleged chemical attack were brought in to meet with the U.N. team.

Today's visit came amid increasing international support for a military response, if it's confirmed that Assad's troops used chemical weapons.

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