Somali pirates hijacked two more cargo vessels and opened fire on a third on Tuesday in attacks that showed their determination to continue striking shipping in the area's strategic waterways.

The capture of the Greek-owned MV Irene E.M. and Togo-flagged MV Sea Horse were a clear sign the sea gangs have not been deterred by two raids in recent days in which U.S. and French special forces have killed five pirates.

NATO Lieutenant Commander Alexandre Fernandes said the Portuguese warship NRP Corte-Real had received a pre-dawn distress call from the St. Vincent and the Grenadines-flagged Irene E.M. as it traveled through the Gulf of Aden.

There was only three minutes between the alarm and the hijack, Fernandes told Reuters aboard the warship. They attacked at night, which was very unusual. They were using the moonlight as it's still quite bright.

The Greek merchant marine ministry said the Irene E.M.'s 22 crew were Filipinos. The East African Seafarers' Assistance Programme, which tracks piracy, said they were all unharmed.

The bulk carrier was sailing from Jordan to India. Its Piraeus-based owners were not immediately available for comment.

Hours later, NATO officials on the NRP Corte-Real said a second ship, the nearly 5,000-tonne MV Sea Horse, had also been seized about 77 nautical miles off Somalia.

They said it was hijacked by pirates on board three or four skiffs, but they had no other immediate details.

Separately, NATO officials said, another gang fired automatic rifles and rocket-propelled grenades at the Liberian-flagged 21,887-tonne Safmarine Asia. They said it managed to escape and that there was no word of any casualties.

Heavily armed gunmen from lawless Somalia have run amok through the busy Indian Ocean shipping lanes and strategic Gulf of Aden, capturing dozens of vessels, hundreds of hostages and making off with millions of dollars in ransoms.

SPECIAL FORCES

Until there is political stability onshore, experts warn, attacks on shipping will continue off its coast.

Piracy is far more complex than any naval patrol, said U.S. analyst J. Peter Pham, of Madison University. It will require more than just the application of force to uproot piracy from the soil of Somalia.

NATO officials said a Canadian warship had sent a helicopter to scout out what was happening on the Irene E.M.

There are hostages so now we will shadow and monitor the situation, Fernandes said.

Foreign navies are patrolling the seas off Somalia. But the pirates have continued to evade capture, driving up insurance costs and defying the world's most powerful militaries.

Snipers on a U.S. Navy destroyer freed an American ship captain on Sunday by killing three Somali pirates holding him hostage in a lifeboat, ending a five-day standoff. Two more pirates died on Friday when French commandos stormed a yacht that had been seized. A French hostage was also killed.

Some fear the bloody assaults by Washington and Paris to free their hostages may raise the risk of future bloodshed. The pirates have vowed to take revenge on U.S. and French citizens.

So far, the sea gangs have generally treated captives well in the hope of fetching big ransom payouts. Many poor and unemployed young Somalis see the gangs as a dazzling alternative to their hard lives, given the quick money to be made.

Most of the groups are based in villages and small towns along Somalia's long coast like Eyl, Hobyo and Haradheere.

Last year, the gunmen grabbed headlines with the world's largest sea hijack -- a Saudi Arabian supertanker carrying $100 million of crude oil -- and the seizure of a Ukrainian ship with a huge military cargo including 33 Soviet-era tanks.

But out of the international limelight, they have been striking regularly for years. They still hold about 260 other hostages, including nearly 100 Filipinos, on 17 captured ships.

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