A US-flagged yacht with three people aboard was attacked by pirates wielding rocket launchers off the coast of Yemen, the Italian Coastguard said yesterday after an Italian freight ship reported a distress call.

?Around 9.45 a.m., an Italian container ship, the Jolly Platino called to say it had heard an SOS message from an American sailing vessel, the Tir Na Nog,? an official from the Rome headquarters of the Coastguard told Reuters.

The Italians informed US authorities in the region of the incident which happened some 25 miles off the Yemen coast. The official said two US and one Dutch military vessel in the area had been told of the attack but he did not know how any rescue attempts were progressing.

Commander Jeff Breslau, a spokesman for the US Navy?s Fifth Fleet based in Bahrain, said: ?Coalition forces are investigating the incident.? He gave no further details.

In Aden, an official at Yemen?s coastguard said he did not have any information about the incident, adding that it had occurred outside the Arab country?s territorial waters. Yemen shares territorial waters with Somalia, whose coastal waters have become among the world?s most dangerous in the 14 years the country has lacked a central government.