(CNN) -- A small overcrowded boat sank off the coast of Malaysia early Thursday, a maritime official said. It's the second boat to go down in two days. Eighteen passengers have been rescued, and the search continues for nine others who are missing. The boat was carrying 27 Indonesian migrants, who were heading back home to Sumatra for the Ramadan holidays, Capt. Hamid Mohd Amin with the Malaysian Maritime Enforcement Agency said. Another boat carrying 97 Indonesians sank in waters off Malaysia's west coast Wednesday, Indonesian authorities said. More than 30 people were missing. The vessel, reportedly carrying undocumented migrant workers heading for Aceh in Indonesia, capsized after leaving Carey Island in Malaysia's Selangor state on Wednesday morning, the Indonesian Ministry of Foreign Affairs told CNN. Malaysian Maritime Enforcement Agency said 60 people have been rescued, and five bodies have been recovered.
Two boats sink in two days off the Malaysian coast . Both were carrying Indonesian migrants . Rescue operations are underway .