They said the vessel, which was flying the Panamanian flag, was carrying trucks, armoured personnel carriers and equipment for military camps.

Also on board were "24 containers whose content was not declared, and which are suspected of containing weapons and ammunition", a statement said.

The ship is now being searched in Sfax.

Media reports said the ship was Russian and bound for Cameroon.

Northwest and southwest Cameroon is home to an English-speaking minority that accounts for about a fifth of the population.

Many English-speakers there have accused the francophone majority of discrimination and that has fuelled a separatist movement.

Sfax is some 300 kilometres (185 miles) from Libya, which has been embroiled in political and military chaos since the 2011 revolution that overthrew strongman Moamer Kadhafi.