Ukraine's leading English-language newspaper since 1995

MOGADISHU (Reuters) - Suspected Somali pirates have hijacked two European-owned tankers within 24 hours in the highest-profile strikes since foreign navies deployed en masse to the region's busy sea lanes.

"These are the biggest attacks this year. The pirates are showing they are very much alive," said Andrew Mwangura of the East African Seafarers Assistance Programme, which monitors piracy in the region from the Kenyan port of Mombasa.

The 9,000-tonne MT Nipayia, a Greek-owned and Panama-registered ship with 19 crew on aboard, was taken on Wednesday 450 miles east of Somalia's south coast, the European Union and NATO said on piracy-monitoring websites.

The 23,000-tonne MT Bow Asir, a Norwegian-owned and Bahamian-registered ship, was seized on Thursday 250 miles east of the south Somali coast, they said.

The attacks show that Somali pirate gangs remain undeterred by a flotilla of ships from Western and Asian countries patrolling to try to prevent a repeat of last year's unprecedented wave of hijackings.

Most of those ships are, however, concentrated in the Gulf of Aden, the gateway to the Red Sea and Suez Canal, whereas the pirates are striking ever further from the Somali coastline.

In another long-distance strike this week, pirates hijacked a yacht from the Seychelles with two men on board. The boat was en route to Madagascar, well south of Somali waters.

SOPHISTICATED TACTICS

Having made millions from ransoms in recent years, the pirates are using increasingly sophisticated boats and radar equipments to spot, chase and capture other vessels.

"They are staying away from the security zone in the Gulf of Aden. They are trying to destabilise the security system the foreign navies have set in place," Mwangura said.

Typically, gangs operate from a "mother" ship that will launch faster speedboats, full of armed men, to board the target. Most crews surrender without a fight.

It was not immediately known what the tankers seized on Thursday and Wednesday were carrying.

Two earlier high-profile cases were resolved earlier this year with the release -- for $3 million each -- of a Saudi oil tanker and a Ukrainian boat with tanks on board.

A record 42 boats were seized off Somalia throughout 2008, with a total 815 crew members taken hostage, according to figures from the International Maritime Bureau watchdog.

That forced up insurance costs and made some shipping firms prefer to go round South Africa than through the Suez.

Shipping bodies warned all boats in the Indian Ocean region to be on alert after this week's attacks. Eager to protect some of the world's most important shipping lanes, the United States, various European nations, Russia, India, China and Japan have all sent ships to patrol the waters off Somalia.

"Once again, the Somali pirates are making fools of all of them," said a diplomat who tracks the piracy phenomenon.

Taking advantage of civil strife onshore, Somali pirates live like kings at home with their ransom earnings, taking extra wives, buying new cars and building fancy homes.