KUALA LUMPUR (AFP) - Two Chinese sailors were rescued alive on Friday (March 23) from the engine room of a sand dredger two days after the vessel capsized off Malaysia, while 12 others remain missing, an official said.

The rescued crew were "conscious but weak", said coastguard official Sanifah Yusof, after being trapped in the JBB Rong Chang 8 since it overturned on Wednesday.

Twelve other sailors - 10 Chinese, one Malaysian and one Indonesian - remain missing.

One Chinese sailor was killed and three others were rescued alive when the Chinese-owned boat first flipped over.

The boat had stayed afloat despite capsizing and hopes were raised that some of the missing had survived after divers heard sounds from inside the hull.

Divers rescued the two Chinese sailors on Friday afternoon, said coastguard official Sanifah.

"We found two victims who are alive, they are Chinese citizens, and they were taken to Muar hospital," he told AFP.

Muar is a coastal town close to where the accident happened.

"We still have hope that everybody is alive," he said, adding the rescue operation would continue into the evening.

It was not clear what caused the accident and the weather in the area was fine at the time.

Dredging sand from coastal areas is a booming and lucrative business. The sand is shipped to wealthy land-scarce areas such as Singapore for reclamation and construction work.

But environmentalists have long argued that the practice damages local communities and ecosystems.

Last year, two foreign vessels manned by Chinese crew were seized off Malaysia's west coast for allegedly conducting illegal sand-dredging.