Transport Malta said this afternoon that it could not so far establish the source of a large oil slick which developed this morning in Birzebbuga.

The slick stretched from the freeport to Pretty Bay.

"At this stage, no local source of pollution could be identified and thus the Authority itself had to take immediate action to start clean-up operations and to remove scattered patches of heavy oil in the contaminated areas, particularly in the fairway, by the jetties, the coastline and around the Freeport Terminals and Oiltanking areas."

The clean-up is still ongoing.

Some ship's hulls at Malta Freeport Terminals were contaminated and will have to be cleaned before their departure to ensure no further spread of pollution.