At least five people have died and 32 others are missing after an overloaded wooden boat carrying 97 suspected illegal Indonesian immigrants sank off Malaysia's western coast, local officials have said.
At least 60 people have been rescued so far, Malaysian authorities said on Wednesday.
The passengers included women and children, and the boat was not fit for a sea voyage, Muhammad Zuri, an official with the Malaysian Maritime Enforcement Agency, said on Wednesday.
Malaysian rescuers were scouring the area for more survivors and had deployed a helicopter, one large ship and four smaller boats in the operation, officials said. Several fishing boats were also helping with rescue efforts.
The MMEA said the boat sank at around 1am local time in the Strait of Malacca off the Malaysian coastal town of Banting.
"This was an illegal boat and all the passengers were Indonesian," Zuri told Reuters.
The boat was heading for Malaysia, Zuri said, but another rescue official said that the vessel was going from Malaysia to Indonesia's northernmost province of Aceh.
The second rescue official said the boat left from Malaysia's Carey Island, an area roughly a fifth the size of Singapore that is dominated by oil palm plantations.
Malaysia, one of Southeast Asia's wealthier economies, has long been a magnet for illegal immigrants from Indonesia and other poorer countries in the region. Many undocumented Indonesians work in Malaysia's vast oil palm plantations, a mainstay of its economy.
Despite periodic crackdowns on illegal workers, Malaysia is home to an estimated 2 million undocumented immigrants or about 7 percent of its 29 million population.