The Malaysian navy says commandos have foiled the attempted hijacking of a Malaysian-owned ship by Somali pirates in the Gulf of Aden.
It says a chemical tanker bound for Singapore came under attack about 550 kilometres east of Oman.
A distress signal from the crew was picked up by a navy ship nearby, and seven pirates were captured following a gun battle.
Officials say they're considering whether to put the men on trial in Malaysia.
The tanker, MT Bunga Laurel, was carrying lubricating oil and ethylene dichloride worth an estimated $US9.8 million.
It is owned by Malaysian International Shipping Corp (MISC) - the world's largest owner of liquefied natural gas tankers.
The incident, which happened close to midnight on Thursday, involved the navy's auxiliary ship Bunga Mas 5 which was located about 25 kilometres away.
The foiled hijacking happened on the same day that South Korea's navy stormed a hijacked ship and killed several pirates in the Arabian Sea.