A Greek-owned chemical tanker with a crew of 18 was attacked by pirates in a protected corridor in the Gulf of Aden, the EU's naval force operating off Somalia said on its website.

"Early on the morning of 8 September, the Merchant Vessel (MV) OLIB G, flagged Malta, was seized by pirates in the East part of the Gulf of Aden... The MV OLIB G was sailing West in the Internationally Recommended Transit Corridor through the Gulf of Aden with a cargo of ballast," the statement reads.

The Nairobi-based organization monitoring piracy off the coast of Somalia, Ecoterra International, said the vessel could be involved in illegal waste dumping activities.

The vessel, with a deadweight of 6,375 tons, has a crew of 18, among which are 15 Georgian and three Turkish nationals.

The organization said two more pirate attacks were reported in the region on Wednesday.

The Antigua and Barbuda-flagged containership MV Magellan Star was targeted and boarded by pirates while on a return voyage from Indonesia.

"The ship's crew locked themselves in a safe room and called for assistance. Apparently there is at present a stand-off between the pirates and navies, which could reach the scene," the organization said.

An attack on the Jamaican-flagged MV Miltiades with 23 onboard and a cargo of fertilizers was thwarted by the military.

"Reportedly five or six pirates were arrested in the unsuccessful attack and the vessel has sailed free," the report said.

A total of 24 vessels with 429 people onboard are estimated to be held by Somali pirates as of September 1.

MOSCOW, September 9 (RIA Novosti)