WASHINGTON (AP) — Secretary of State John Kerry says there is "undeniable" evidence of a large-scale chemical weapons attack in Syria, with intelligence strongly pointing to Bashar Assad's regime. Kerry says "this international norm cannot be violated without consequences."

Kerry's tough language Monday marked the clearest justification yet for U.S. military action in Syria.
Officials say President Barack Obama has not decided how to respond to the use of deadly gases.

The White House said last year that type of warfare would cross a "red line." The U.S., along with allies in Europe, appears to be laying the groundwork for the most aggressive response since Syria's civil war began more than two years ago.