NAIROBI, Kenya — NATO warships safely escorted a cargo of supplies through the pirate-infested waters off Somalia today and hijackers holding an arms-laden Ukrainian vessel said its operators do not want to negotiate for the weapons.

The NATO escort for a ship supplying African Union peacekeeping troops in Somalia was the first such mission for the alliance's seven-ship flotilla, which arrived in the region over the weekend to conduct anti-piracy patrols and guard World Food Program aid shipments.

"The operation is moving well," NATO Secretary-General Jaap de Hoop Scheffer said in Brussels. "The present state of play is that a NATO ship just finished escorting a ship which was bringing in supplies to the Burundi battalion ... in Somalia."

Somalia, caught up in an Islamic insurgency, has not had a functioning government since 1991. It has no navy or coast guard and cannot guard its coastline, which includes the Gulf of Aden, one of the world's busiest and most dangerous shipping lanes.

The Ukrainian cargo ship MV Faina, hijacked Sept. 25 with a cargo of 33 battle tanks and heavy weaponry, focused international attention on the pirate menace off the Horn of Africa. Ships of the U.S. Navy's 5th Fleet have surrounded it for a month to be sure the cargo does not get into the hands of insurgent groups linked to al-Qaida.

The pirates who hold the Faina said Monday that its operator wants to negotiate only for the release of the vessel and crew of 20 — and not its cargo.

The pirates' spokesman Sugule Ali said they received a fax on Friday from Viktor Murenko, the head of ship operator Tomex Team, saying Kenya had declined to pay any ransom for the cargo it claims.

The Murenko letter said the pirates are at, "liberty to destroy or throw the weapons to the sea if they deemed that fit," Ali told The Associated Press via satellite phone from the Faina.

In Russia, a spokesman for ship owner Vadim Alperin said such a thing was physically impossible as there was no way to unload or destroy the cargo with U.S. forces surrounding the ship.

"The ship owner doesn't care about the cargo, he has already cursed it in all ways possible," said Mikhail Voitenko. But he said that it was impossible to separate the cargo from the ship. "Physically it's impossible."

Kenya's Foreign Affairs Minister Moses Wetangula repeated that the government would not pay any ransom, and told the AP that Tomex Team is responsible for the cargo until it is delivered.

Ali said the pirates passed on a copy of Tomex Team's letter to the U.S. Navy, and that the Faina's captain, Viktor Nikolsky, confirmed the signature on the letter belongs to his boss.

Lt. Nathan Christensen, a U.S Navy spokesman in Bahrain, would not say whether it had received a copy of the letter.

He said on Monday that American ships guarding Faina, which is anchored off the coast, remain in daily contact with its crew and the pirates.

"We are still actively monitoring the ship, making sure the crew is healthy and the cargo is not offloaded," Christensen said, speaking by telephone from 5th Fleet's headquarters.

Several other nations have announced plans to deploy warships to the region, and the European Union is planning to dispatch its own naval squadron by December.

The Russian missile frigate Fearless also has arrived off the Somali coast, and Moscow has announced it will cooperate with the West on fighting the pirates.

About 20,000 ships pass annually through the Gulf of Aden.