Libyan authorities have released an Italian high-seas tugboat held in the port of Tripoli for more than a month with 11 crew aboard, the Italian foreign ministry and the ship's owner said. The tug had been due to come to Malta today but changed plans and is going straight to Italy. 

The foreign ministry expressed its "satisfaction over the positive outcome" of the ordeal, while Mario Mattioli of the Naples-based oil industry shipping firm Augusta Offshore said he was "very happy that the crew was freed."

The Asso 22's crew included eight Italians, two Indians and a Ukrainian.

The crew will board an Italian NATO ship on patrol in the area for preliminary medical checks.

The 75-metre (250-foot) tug had arrived in Tripoli last month to evacuate workers from the Libyan state oil company NOC as war clouds gathered over Libya.

Armed men seized the vessel on March 19, shortly before an international coalition including Italy began air strikes against forces loyal to Libyan strongman Moamer Kadhafi.

There have been intensive diplomatic efforts to get the ship released, with Italy earlier saying the crew were being held as "hostages".

Foreign Minister Franco Frattini thanked the crisis unit handling the affair "and all the institutions that followed developments in the situation day by day."