GAROWE, Somalia - Somali pirates have freed a Yemeni cargo ship they seized last week after successful talks between regional authorities, local clan elders and the gunmen, a local official said on Wednesday.

A surge in attacks at sea this year in the busy Gulf of Aden and Indian Ocean shipping lanes off Somalia has pushed up insurance costs, brought the gangs tens of millions of dollars in ransoms, and prompted foreign warships to rush to the area.

"The Yemeni ship was released last night after long discussions," Ali Abdi Aware, state minister of Somalia's northern province of Puntland, said. "It left Eyl and is heading to Yemen. The crew are safe and no ransom was paid."

The MV Amani, owned by Yemeni shipping firm Abu Talal, has seven sailors on board. It was seized on November 25 as it carried 507 tonnes of steel from Yemen's Mukalla port to Socotra Island.

Eyl is a remote former fishing village on the Puntland coast that has become well-defended base for the pirates.

There have been nearly 100 attacks in Somali waters this year, despite the presence of several foreign warships. The sea gangs are holding about a dozen ships and nearly 300 crew.

The captured vessels include a Saudi supertanker loaded with $100 million of oil, the Sirius Star, and a Ukrainian cargo ship carrying some 30 Soviet-era tanks, the MV Faina.

On Tuesday, the UN Security Council renewed its authorisation for countries to use military force against the gunmen operating off the anarchic Horn of Africa nation.

The resolution extended for one year the right of nations with permission from Somalia's interim government to enter Somali waters to pursue and attack pirates. The US-drafted text was adopted unanimously by the 15-nation council.

France's UN ambassador, Jean-Maurice Ripert, said the move sent a very strong signal and would allow the European Union to begin an air and naval operation off Somalia on December 8.

That mission is expected to involve five to six ships at any given time, plus maritime surveillance aircraft.