NAIROBI, Kenya (AP) — Somali pirates hijacked two ships on, including a vessel carrying fertiliser, in a series of attacks that shows the pirates are moving further east, officials said.

And Kenyan security forces have arrested Somali pirates in Kenyan waters for the first time, taking 11 suspected gunmen into custody after a failed attempt to hijack a fishing vessel, police said.

The hijacking of the Malta-flagged MV Frigia took place more than 1,000 miles out at sea and represents a substantial increase in the pirates' range, said Cmdr. John Harbour, spokesman for the EU Naval Force.

The attack took place more than 400 miles outside where the naval force operates.

The second hijacking, of the Bermuda registered MV Talca, took place about 120 miles off the coast of Oman, said Harbour.

It was 60 miles from the easternmost limits of the 1.5 million square mile area patrolled by around 35 warships from the European Union Naval Force, Nato, the US and other nations.

The Talca, a refrigerated cargo vessel, had 23 Sri Lankans and one Filipino and one Syrian on-board. It was heading from Sokhna in Egypt to Busheir in Iran. It had already passed through the International Recommended Transit Corridor, which is patrolled by warships and maritime patrol aircraft from EU NAVFOR, NATO, Combined Maritime Forces and other navies.

The hijacking of the Frigia is potentially more complicated. It is unclear if its cargo of fertiliser is nitrate-based, which could be used for bomb-making in Somalia. The country's beleaguered government is battling an Islamic insurgency.

Pirates in the past have hijacked ships carrying weapons and fuel, but they have never turned over potentially dangerous cargo to militants.

Naval warships generally monitor such hijacked ships very closely and it is difficult to unload cargo without proper port facilities. Using fertiliser to make bombs also requires some expertise and the Somali Islamists have not used such bombs before.

Ayhan Ugurlubay, a spokesman for the Turkey-based Karya shipping company, said officials received a distress signal from the Frigia but have had no contact with the ship since then.

The ship was carrying fertiliser from Israel and was heading for Thailand, he said. The ship had 19 Turks and two Ukrainians on board.

"We carried out all the required procedures. The ship sailed through the dangerous zone in a convoy, escorted by (Turkish navy frigates) the Gediz and Gelibolu," he told Turkey's state-run Anatolia news agency. "The incident occurred one and a half days after it left the naval convoy ... It is the first time that a ship has been kidnapped so far away," he said.

Experts say piracy will continue to be a problem until an effective government is established on Somalia's lawless shores. Somalia has not had a functioning government for 19 years. Kenya is one of the few east African countries prepared to put pirates on trial and has more than 100 suspects in jail facing charges. But, so far, the Somalis have all been captured by foreign navies patrolling the Indian Ocean and Gulf of Aden.

"Yes, police have arrested the 11 suspects, believed to be pirates in Kiunga area. They are in custody," said Provincial Criminal Investigation Officer (PCIO) Nyagah Reche. Police sources said the suspects ran out of fuel at sea, hijacked a fishing boat and ordered the crew to sail to Somalia. But one of the crew made a telephone call which led to the intervention of Kenyan security forces based in Lamu.

One source said the suspects ditched their weapons and skiffs when they realised the police were nearby. "Transport arrangements are being made to bring them to Mombasa from Lamu, so that they answer to several charges which are being prepared as investigations continue," said Reche. Somali pirates have plagued the busy shipping lanes in the Gulf of Aden and Indian Ocean for years. Emboldened by ever higher ransom payments, Somali sea gangs accounted for more than half of piracy incidents worldwide in 2009.

Foreign navies patrolling the areas have prevented some hijackings and captured scores of suspected gunmen. But finding somewhere to put them on trial has sometimes proved problematic, and some navies have let suspects go free.

Earlier this month, a Kenyan court sentenced seven Somalis to 20 years in prison for piracy after British Royal Navy forces arrested them in 2008 trying to attack a Danish cargo vessel. Ten more pirates are serving seven-year jail terms in Kenya.

The French navy has also taken a large number of suspected pirates to Puntland, the semi-autonomous northern region of Somalia where several sea gangs are believed to operate from.

On Saturday, a judge in Puntland sentenced 22 suspects to six years in jail for acts of piracy in waters off Somalia.