SAN FRANCISCO (AP) — It’s unclear what caused Saturday’s crash-landing of an international jetliner at San Francisco’s airport, but passengers and witnesses say the plane appeared to come in too low and may have clipped a seawall at the end of the runway.

Asiana Airlines describes the pilots as a “skilled,” veteran crew, three of them with more than 10,000 hours each of flight time and a fourth with 5,000.

Chinese state media are identifying the two people killed in the crash as a pair of 16-year-old girls from a school in eastern China. Their bodies were found outside the wreckage of the jumbo jet.

More than 180 people were taken to hospitals with injuries, 49 of them critical.

The flight originated in Shanghai, with a stop in Seoul, South Korea. There were 16 crew members and 291 passengers aboard, including 61 Americans and 141 Chinese, about half of them students and teachers.

A National Transportation Safety Board team is investigating the cause.