Berlin - A German warship warded off a suspected piracy attack on a German cruise ship in the Gulf of Aden, a defence ministry spokesman confirmed Friday.

The naval frigate Mecklenburg-Vorpommern chased off two suspicious speed boats on November 28 with three bursts of fire from a machine-gun, the spokesman said, confirming reports from Thursday.

A spokesman for Transocean Tours in Bremen, operators of the cruise ship, said the 492 passengers and crew on board the MS Astor had not noticed the incident. The ship also had not asked for help.

The suspicious boats disappeared quickly into Yemen's territorial waters, the tour operator said.

Transocean said the speed boats had approached to within 3 nautical miles of the cruise ship when the frigate intercepted them. The warship fired warning shots after the speed boats began to accelerate.

The defence ministry said it was not clear whether the boats were manned by pirates or by fishermen who had behaved in an ambiguous manner.

The cruise ship was bound for Dubai, where it arrived on Tuesday.

Some 63 incidents of piracy have been recorded in waters off the Somali Coast and the Gulf of Aden in the first nine months of this year, according to the International Maritime Bureau.

Germany is due to decide on Wednesday whether to contribute up to 1,400 military personnel to a European Union security mission to combat piracy off the coast of Somalia.

Defence ministry sources said the personnel would be used to crew a frigate patrolling the Horn of Africa or provide security on German-owned merchant vessels in the region.

The current United Nations mandate for anti-piracy operations in the region expires on December 2.

The UN Security Council is close to passing a new resolution that authorizes a European Union fleet to fight piracy, according to German Foreign Minister Frank-Walter Steinmeier this week. (dpa)