The speedboat was traveling from Padang Bai port in eastern Bali to nearby Gili Island when the fire broke out after 9:30 a.m. local time.

The tourist vessel was roughly 600 feet (200 meters) from port when flames took hold, said Heronimus Guru, deputy of operations for the National Search and Rescue Agency.

Eyewitness Dex De told CNN he works nearby and ran to the port when he heard the news. He said many of the passengers were injured.

"Most of them were foreigners," he said. "Some were crying; some panicked."