A chemical oil tanker foiled a hijack attempt by pirates near the Omani port of Salalah on Sunday, a day after a tanker and crew were snatched from inside the port in front of the coast guard.

"Pirates in a skiff chased and fired upon a chemical tanker," according to the International Maritime Bureau's anti-crime arm.

 "The pirates made several attempts to board the tanker and finally aborted the attack due to the evasive manoeuvres made by the tanker."

On Saturday, pirates successfully seized the empty MV Fairchem Bogey chemical oil tanker from its anchorage at the port in the mouth of the Gulf of Aden, taking 21 Indian crew members hostage and heading south to Somalia, Mumbai-based Anglo Eastern Ship Management said.

"We can now confirm that the Fairchem Bogey is now in Somali waters," the tanker manager said in a statement.

"The Master has been in contact with us, reconfirming safety of the crew. We are still waiting to make first contact with the hijackers."

Anglo-Eastern said the Omani Coast Guard approached the vessel shortly after it was seized from its anchorage in the port but backed off when the pirates warned that the captured crew might be harmed.

The Bogey, which had armed guards on board when it sailed through the Gulf of Aden on its way to unload at the Saudi port of Al Jubail on August 18, was unprotected when it was taken on August 21 after dropping the security team off in the Omani capital Muscat on August 10, the company said.

Several oil tankers have been attacked in the pirate-infested Gulf of Aden, with their valuable cargoes being used by pirates to demand ransoms.-Reuters