Spanish arms control activists say a Saudi ship they suspect is carrying weapons for possible use in Yemen has left the port of Santander and is on its way to Genoa, Italy.

Alberto Estevez of the Control Arms Coalition of human rights and aid groups, which is trying to stop arms reaching conflict zones, has told The Associated Press that the Bahri Yanbu cargo ship left the northern Spanish port Monday after loading two containers.

Spanish government officials had no immediate comment.

The ship was due to pick up weapons when it arrived in France last Friday but apparently left without doing so amid protests and legal challenges.

Countries are under pressure not to send arms to Saudi Arabia, amid concerns they are being used against civilians in Yemen.