A Spanish court has issued a warrant for the capture and search of two American exploration ships suspected of removing sunken treasure from Spanish waters.

The ships, belonging to Odyssey Marine Exploration, which is based in Florida, are docked in Gibraltar and cannot leave because Spain controls the waters surrounding the British enclave.

A Spanish Culture Ministry spokeswoman said investigations by the Civil Guard, the Defence Ministry and Spanish prosecutors produced sufficient evidence to suspect that the vessels were operating illegally in the Alboran Sea, the western-most part of the Mediterranean Sea.