COLOMBO, Sri Lanka (AP) - The U.S. ambassador says America had "no prior knowledge" of a threat in Sri Lanka before the Easter bombings that killed more than 350 people.

Ambassador Alaina Teplitz made the remarks Wednesday to foreign journalists at the U.S. Embassy in Colombo. Teplitz said there was a "right-sized" team of FBI agents and U.S. military officials assisting Sri Lanka in the investigation.

Teplitz also said, "clearly there was some failure in the system" for Sri Lanka prior to Easter bombings. Sri Lanka's government has acknowledged it received warnings of a local extremist group threatening churches and the prime minister said some people might lose their job over the intelligence failures.