Pirates have hijacked a Singapore-owned oil tanker off the coast of Nigeria. A navy spokesman said, it was not clear where the vessel had been taken. He said efforts are made to locate and rescue the vessel, Abu Dhabi Star.

The International Maritime Bureau told the AFP news agency that 23 crew members were on board when the tanker was captured and they had locked themselves in a safe room.

Analysts say, piracy is increasing in parts of West Africa.

In the first six month of this year, the International Maritime Bureau says it has recorded 17 pirate attacks in Nigerian waters this year.