Five crew members of a Dominican-registered dredger were missing after a collision with an Indonesian-registered tanker in Singapore's territorial waters on Wednesday, Singapore's Marine Port Authority (MPA) said.
The missing include four Chinese nationals and one Malaysian, the MPA said. Seven other Chinese nationals have been rescued.
The dredger capsized and is currently partially submerged, while the tanker reported damage on starboard, the MPA said.
Singapore authorities are conducting search and rescue operations and the Singapore Navy has deployed three patrol craft. The Singapore Air Force has also deployed a helicopter to conduct an aerial search, the MPA said.
There has been no disruption to shipping traffic in the Singapore Strait.