Nairobi- Somali pirates on Monday seized a Philippine- flagged cargo ship in the Gulf of Aden as the European Union agreed to send a fleet of anti-piracy frigates to the region, a maritime official said Tuesday.

Andrew Mwangura, of the Kenya-based East African Seafarers' Assistance Programme, said that the Stolt Strength was hijacked on Monday along with its 23 Filipino crew.

The Stolt Strength's sister ship, the Stolt Valor, was also seized in the Gulf of Aden two months ago.

On Monday, the EU agreed to send five to seven frigates plus support aircraft to deploy to the Horn of Africa around mid-December in "Operation Atalanta."

The force is tasked with protecting merchant ships and aid vessels bound for Mogadishu.

International attention has focused sharply on the Somalia pirate situation in recent months following a spate of attacks and kidnappings and the capture of a Ukrainian ship laden with heavy weaponry.

In addition to the EU fleet, NATO, the US-led military alliance and Russia have all sent ships to the area.

However, the heavily armed pirates, who operate from small launches, appear undaunted as they continue to seize ships in search of multimillion-dollar ransoms.

Some 32 ships have been hijacked this year and many more attempts have been foiled, according to the International Maritime Bureau.

Eleven ships remain in the hands of pirates, including Ukraine's MV Faina.

Pirates initially asked for a 20-million-dollar ransom for the ship, which was carrying Soviet tanks to the Kenyan port of Mombasa, and then threatened to blow up the ship and its crew. However, a stand-off has now developed.

The surge in piracy has coincided with a rise in violence in Somalia itself, where authorities in the central and southern region are battling a bloody insurgency.

The weak central government has been unable to suppress either the insurgency or the growing piracy.

Somalia has been engulfed in chaos and civil war since the fall of dictator Mohamed Siad Barre in 1991. (dpa)