Somalian pirates freed a chemical tanker and its 23 Filipino crew members Tuesday after holding them hostage in the Gulf of Aden for more than five months, the ship owner and officials said.

The release came a day after a separate group of bandits freed the Lebanese-owned food aid freighter MV Sea Horse after receiving $100,000 US from Somali businessmen. At least 16 other ships with nearly 300 crew remain in the hands of Somalian pirates.

The Philippine company Sagana Shipping Inc. declined to say whether it paid any ransom for Tuesday's release of its ship, MT Stolt Strength.

Securing the safe release of the vessel and crew was "difficult and protracted" and the company was "extremely pleased" with the result, Sagana spokesman Dexter Custodio said in a statement.

"They have been released, thank God!" said Doris Deseo, wife of Carlo Deseo, the ship's 31-year-old third mate. "They are no longer in the hands of the pirates. I am super happy. That's the only thing we have been waiting for."

The Stolt Strength was seized Nov. 10, 2008, by pirates in the Gulf of Aden while it was carrying a cargo of phosphoric acid from Dakar, Senegal, to Kandla, India, Custodio said. Earlier reports had said the ship was heading to Japan.

Analysts blame Somalia's nearly 20 years of lawlessness for fuelling piracy's rise.

Attacks have risen markedly in recent weeks, including one on Monday when pirates fired rockets at a Maltese-flagged ship off Yemen's coast. NATO warships scrambled helicopters in defense of the ship, and pirates escaped with no damage to the cargo ship.

NATO forces have helped fend off several attacks in recent days, but have released the culprits because they had no jurisdiction to arrest them. In some cases, neither the pirates nor their targets were nationals of NATO countries.

Clinton, Verhagen seeks NATO help

In Washington, U.S. Secretary of State Hillary Rodham Clinton and Dutch Foreign Minister Maxime Verhagen met Monday and said they will seek authority for NATO to arrest pirates.

Family members of the Stolt Strength crew told The Associated Press that the Somalian pirates earlier demanded $5 million U.S., but that the amount had been reduced to about $2.2 million last week.

Custodio said he could not comment on whether ransom was paid.

"I have no idea because it was the company's crisis management team that has the data about that," he told the news service.

A NATO spokesman said the ship would head to Mombasa, Kenya, arriving in about a week. One crew member needs medical attention, but does not have a serious problem, Lt.-Cmdr. Alexandre Santos Fernandes said.

"The main concern now is to refuel the ship," Fernandes said.

Eduardo Malaya, spokesman for the Philippine Department of Foreign Affairs, said the ship was released around 11:35 a.m. local time and was heading to "safer waters" under escort of international ships.

Meanwhile, Abduhl Wali-i-Musi, the sole surviving Somalian pirate allegedly involved in the hostage-taking of U.S. commercial ship Capt. Richard Phillips, arrived in New York late Monday. He is expected to appear in Federal Court on Tuesday.

No charges have been publicly filed yet, but the suspect could face charges that carry a maximum sentence of life in prison.