HANOI, Vietnam » Vietnamese authorities said Saturday they detected the last signal from a missing Malaysia Airlines flight off Vietnam’s southwest coast over the South China Sea.

Pham Hien, a Vietnamese search and rescue official, said that the signal was detected 140 miles southwest of Vietnam’s southernmost Ca Mau province.

Lai Xuan Thanh, director of Vietnam’s civil aviation authority, said that the plane was over the sea and bound for Vietnamese airspace but air traffic officials in the country were never able to make contact.

The Malaysia Airlines Boeing 777-200 carrying 239 people lost contact early Saturday morning between Malaysia and Vietnam.