The five-man crew of a small Maltese-managed tanker are in custody in Tripoli on suspicion of smuggling fuel, the Tripoli Herald said today.

They were arrested three weeks ago when their vessel, the Sun Oil, was towed to Tripoli by an Italian freighter which had reportedly found it drifting in Libyan waters.

The detention of the Moldovan-flagged, tanker was only made public on Saturday when the Bulgarian Foreign ministry requested clarification of the fate of two of its citizens, who are among the crew.

The vessel was reportedly loaded with petrol and had been heading for Malta.

The smuggling of highly-subsidised Libyan fuel to neighbouring states, including Malta, has long been a major source of income to some militias and criminal gangs, the newspaper said.