A large group of al Qaeda terrorists was believed headed for Santa Catalina Island on a merchant ship laden with weapons, The Washington Times reported Tuesday. The Federal Bureau of Investigation said the plot remains unsubstantiated.

Federal authorities have been searching for the vessel, which was reportedly ferrying as many as 40 al Qaeda and is said to have left a Middle Eastern port last month to carry out terrorism in Los Angeles, according to The Times.

The FBI has been investigating the purported terror mission for several weeks, but has not found evidence to corroborate details of the plan, The Times cited authorities as saying.

The article quoted one FBI official who said the threat could not be entirely discounted, but that an investigation involving interviews of suspects in the Los Angeles area has "greatly reduced" the bureau's concerns. FBI officials declined further comment.

The rumor of a seaborne al Qaeda infiltration has its origins in a classified intelligence report distributed within the government in late May, at about the same time the ship would reportedly have arrived at Catalina Island to disburse the men and weapons, according to The Times.

By Marc Salvatierra, with material from The Washington Times.