Somali pirates holding an arms-laden Ukrainian tanker off Somalia may extend the deadline on their threat to destroy the vessel, a spokesman said Monday.

In Kiev, angry relatives of the ship's crew members demanded that Ukraine's government stop delaying and just pay a multimillion-dollar ransom to the pirates.

The pirates have said they will destroy the MV Faina on Monday night or early Tuesday unless a ransom is paid. They may extend the deadline following requests from the ship's owner and other unidentified people, pirate spokesman Sugule Ali said.

The pirates were reviewing the deadline to see whether to, "modify it and if that is not possible, to execute it," Ali told The Associated Press in an interview by satellite telephone from the ship.

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The crew members' relatives tried and failed to meet with Ukrainian President Viktor Yushchenko in Kiev over the ransom demand, which began at $20 million and has since appeared to drop. They vowed not to leave the president's office.

"We will not leave until we meet with the president," said Yelena Priskha, 41, as she stood outside Yushchenko's office. "We will sleep on the stairs and will collect the money ourselves."

Her husband Olexandr is one of 20 crew on the MV Faina, which is carrying 33 battle tanks and other heavy weapons that the U.S. and other nations fear could fall into the hands of Al Qaeda-linked Somali insurgents.

An official at the president's office said Yushchenko was in a meeting and could not see the relatives immediately.

Ukraine's government says it is against using force in the dispute, but as a matter of policy it will not negotiate with terrorists. Somalia's government has authorized nations to use military force to end the hijacking.

Svetlana Mgeladze, 56, whose son Roland is on the Faina, accused authorities of being more interested in the arms trade than in saving the crew's lives.

"They talk about their weapons here and I have a 22-year-old son there," she said.

The ship's operator, the Tomex Corp. of Odessa, Ukraine, has not commented on negotiations.

The threat by the pirates on the Faina was unusual. Pirates operating off Somalia rarely harm their hostages, instead holding out for ransoms that often exceed US$1 million.

Pirates have seized more than two dozen ships this year off the Horn of Africa, but the Faina has drawn intense interest because of its military cargo. U.S. warships have surrounded it since the beginning to prevent pirates from unloading the weapons.

International pressure on the pirates is growing. NATO is sending seven ships to the treacherous waters where the Faina is being held, and the Russian missile cruiser Intrepid is on its way as well.

The ship's Russian captain died of a heart condition soon after the hijacking.