The Dutch navy captured 13 Somali pirates and seized a haul of weapons off the coast of Oman after the pirates attacked a merchant ship, the Defense Department reported Thursday.
Armed pirates on speedboats tried to board the Antigua and Barbuda-flagged BBC Togo, but were repelled after firing on the vessel.
Ministry spokesman Robin Middel said "it didn't go easily for the pirates" because the BBC Togo had taken precautions such as barring stairwells with barbed wire.
The pirates then fled to a larger fishing boat, 150 nautical miles (280 kilometers) south of the western town of Salalah, where a Dutch frigate captured them Wednesday evening, Middel said.
"A large amount of weapons were discovered on board, among which were AK-47s, rocket-propelled grenades, ammunition, boarding hooks and ladders," the ministry said.
The pirates were arrested and are being held on the HMS Evertsen, Middel said. They are believed to be Somalis.
The Dutch frigate is leading an EU naval force in the region to protect food shipments to Somalia and to combat piracy.
Middel said officials had identified the men captured on the fishing boat as those who had attacked the BBC Togo from photographs taken by the merchant ship's crew. Those photos would also make it possible to prosecute them.
"Most of the time it's difficult to identify pirates, but this time you have pictures and eyewitnesses," he said.
The EU has agreements with Kenya and the Seychelles to turn over captured pirates to them, and the pirates could face prosecution in one of those countries, the Dutch statement said.
Two Tanzanian fishermen said the pirates had held them hostage for months and used their boat as a floating operations base, the statement said. The Dutch navy returned the fishing boat to the two Tanzanians.
Separately Thursday, another group of Somali pirates freed cargo ship MV Charelle and 10 crew members who had been held hostage since June 12.
European Union Navel Forces Cmdr. John Harbour said he did not have any information on whether a ransom was paid or not. Ship owners typically keep information on ransoms secret.
Pirates are still holding hundreds of crew and a dozen vessels hostage in Somalia.
Piracy has remained at high levels this year in the busy shipping lanes along the Gulf of Aden and the Indian Ocean near Somalia, despite a growing number of international warships and extra safety precautions taken by merchant vessels.
Somalia has not had an effective central government since 1991 as regional warlords vie for power, and impoverished young men have increasingly taken to piracy in recent years in hopes of a big ransom payoff.
Associated Press writer Katharine Houreld contributed to this report from Nairobi, Kenya.