KUALA LUMPUR, Malaysia (AP) — Malaysia intelligence agencies are investigating how up to four passengers with suspect identities were able to board the missing Boeing 777 jet, the government said, as planes and ships from across Asia resumed the hunt Sunday for the plane.

There was still no confirmed sighting of wreckage from the Boeing 777 in the seas between Malaysia and Vietnam where it vanished from screens early Saturday morning en route to Beijing from Kuala Lumpur with 239 people on board. The weather was fine, the plane was already cruising and the pilots had no time to send a distress signal — unusual circumstance for a modern jetliner to crash.