Somali pirates have seized another Malaysian tanker in the latest such attack in the waters off the coast of Yemen.
The Bunga Melati 5 was carrying 30,000 tonnes of petrochemicals to Singapore from Saudi Arabia.
Malaysian national carrier MISC said 36 Malaysians and five Filipinos were aboard when it was hijacked in international waters.
Somali pirates have hijacked at least 30 ships in the area so far this year.
Last week they seized four in 48 hours, and are now holding about 130 crew hostage on at least eight vessels from Malaysia, Thailand, Japan, Germany, Nigeria and Iran.
Nearly 20,000 ships pass through the Gulf of Aden each year, heading to and from the Suez Canal.