Armed people on a skiff attacked an oil tanker as it passedthrough the Strait of Hormuz, the world's most important traderoute for crude shipments, a group monitoring piracy at seasaid.

The unidentified attackers fired twice by machine gun at thetanker's accommodation area and bridge at about 2:15 p.m. localtime yesterday, according to a notice on the London-basedInternational Maritime Bureau's website. The craft aborted itsattack after the vessel made evasive maneuvers. U.S. and Europeanmilitary authorities are investigating, Lt. Commander David Benham,a spokesman for the North Atlantic Treaty Organization's AlliedMaritime Command, said today.

The Strait of Hormuz is a transit channel for about 17 millionbarrels of crude daily, according to the U.S. Energy InformationAdministration, which ranks the trade lane as the world's mostimportant chokepoint for oil. NATO coordinates naval vessels toprotect commercial ships from Somali pirates operating in theadjoining Indian Ocean and nearby Gulf of Aden.

“We have no reason to believe it's related to Somali piracy,”Benham said by phone from Northwood, England. “Most pirate attackstake place in the main commercial shipping corridor in the IndianOcean.”

The NATO Shipping Centre, which shares piracy alerts withcommercial ships, said the vessel attacked yesterday used firehoses to deter the smaller craft, which turned away after coming towithin five meters of its target. Two other merchant ships reportedbeing approached in or near Hormuz yesterday, according to separatereports on the center's website.

Two green-colored skiffs carrying three to four armed people inmilitary clothing came to within 150 meters of one vessel beforeturning toward the Iranian coast. Another vessel took evasiveaction outside the Strait for about 25 minutes after two smallercraft neared it. One of the smaller ships was seen carrying aladder.

The only other incident reported in the past year near Hormuzwas on March 6 when a merchant vessel was approached in the Gulf ofOman by three skiffs, according to the NATO Website.