Cruise ships in the Mediterranean could be targeted in a terror attack by militant groups armed with Russian weapons, a top British commander warned yesterday.

Vice Admiral Clive Johnstone, the UK's highest naval officer in Nato, said Islamic State's spread into Libya had cast an 'uncomfortable shadow' over the sea.

In stark remarks, he revealed the IS terror group are attempting to build a navy to wage war against the West.

He said there was a 'horrible opportunity' that a 'very high quality weapons system' would be used to hit ships crossing the sea, having 'extraordinary implications' for the Western World.

Speaking onboard a Spanish Nato ship in London yesterday, Vice Adm Johnstone said that Nato must not get 'hustled out' of eastern Mediterranean water space.

He said: 'Nato mustn't think the Mediterranean is just about immigration. It is the spread along the North African seaboard, it is the Daesh entry into Libya, it is the Daesh control of Sirte and other places, which has an uncomfortable shadow over maritime trade and maritime access.'

Conflict and revolt across the region had made it more difficult for Nato countries, including Britain, to 'ascertain what threats are there', he said.

He added: 'At the same time, we are tracking the spreads of really quite capable Korean, Chinese and Russian hardware, into bodies such as Hamas and Hezbollah and other places.'