ON BOARD CORTE-REAL (Reuters) -- Dutch commandos have freed 20 Yemeni hostages and briefly detained seven pirates who had forced their captives to sail a "mother ship" attacking vessels in the Gulf of Aden, NATO officials said.
Meanwhile, pirates seized a Belgian-registered ship and its 10-member crew, including two Belgians, further south in the Indian Ocean. A pirate source said the vessel, the "Pompei," would be taken to the coast.
Sea gangs from Somalia have captured dozens of ships, taken hundreds of sailors prisoner, and made off with millions of dollars in ransoms despite an unprecedented deployment by foreign militaries off the Horn of Africa.
NATO Lieutenant Commander Alexandre Fernandes, speaking on board the Portuguese warship "Corte-Real," said the 20 fishermen were rescued after a Dutch Navy frigate on a NATO patrol responded to an assault on a Greek-managed tanker by pirates firing assault rifles and grenades.
The Dutch ship, the "HNLMS De Zeven Provincien," chased the pirates, who were on a small skiff, back to their "mother ship" -- a hijacked Yemeni fishing dhow.
"We have freed the hostages, we have freed the dhow and we have seized the weapons.... The pirates did not fight and no gunfire was exchanged," Fernandes said. The "Corte-Real" is also on a NATO mission.
He said the hostages had been held since last week. The commandos briefly detained and questioned the seven gunmen, he told Reuters, but had no legal power to arrest them.
"NATO does not have a detainment policy. The warship must follow its national law," he said.
"They can only arrest them if the pirates are from the Netherlands, the victims are from the Netherlands, or if they are in Netherlands waters."
He said an unexploded rocket-propelled grenade was later found on board the tanker, the Marshall Islands-flagged "MT Handytankers Magic" managed by Roxana Shipping SA of Greece.
A Belgian government crisis-centre spokesman said concerns grew for the "Pompei," a dredging vessel, after it put out two alarm signals early on April 18 when it was about 600 kilometers from the Somali coast en route to Seychelles.
A pirate source who said he was on board the "Pompei" told Reuters in Mogadishu by telephone that the pirates would take it to a coastal base.
"We have hijacked a Belgian ship. We will take it to Haradheere," he said. He declined to be named.