Somali pirates freed 20 Filipino seamen from a hijacked ship they held up for more than 80 days, officials said Friday, as the government doubled the pay of sailors passing through pirate-infested international waters.

Foreign Affairs Undersecretary Esteban Conejos said the all-Filipino crew of the Japanese-operated bulk carrier Stella Maris seized in July was freed late Thursday. He said the sailors were "well and safe" and their ship was headed to Muscat, Oman.

He said 47 Filipinos on three other ships were still in the hands of Somali pirates.

Meanwhile, a Somali official said a ship carrying cement to the East Africa country was hijacked late Thursday. The hijacking came after NATO joined a growing international force to protect vessels off the perilous coast.

Labor Secretary Marianito Roque, meanwhile, said the Philippine Overseas Employment Administration approved a resolution doubling the salary of Filipino sailors passing through dangerous waters.

Roque said the agency gave Filipino crewmen the option to disembark at the nearest safe port before their vessels sail through dangerous waters like the Gulf of Aden. Recruiting agencies and shipowners agreed to abide by the government's decision, he said.

More than 270,000 Filipinos work on foreign vessels, accounting for about a third of the world's shipping crews.

Government records showed 117 Filipino crewmen have been seized by Somali pirates in 11 attacks since April. There were 20 Filipinos seized in one incident in 2006 and 10 in two attacks last year.

The pirates have released most of the hostages. It was not clear if a ransom was paid but hostages in Somalia are usually freed in exchange for money.

Ali Abdi Aware, foreign minister of the semiautonomous region of Puntland in Somalia, said the crew of the ship hijacked late Thursday is believed to be Syrian and Somali.

NATO said Thursday it would send seven ships to the treacherous waters where pirates are negotiating the release of the MV Faina, a Ukrainian ship hijacked two weeks ago.

Pirates have seized more than two dozen ships off Somalia's coast this year but the MV Faina has drawn the most international concern because of its dangerous cargo _ 33 tanks and other heavy weapons.