A Russian cargo ship that Ukraine claims was sent to Syria to collect weapons has sunk in the Mediterranean Sea, according to officials in Moscow, Sky News reports.

Two crew members are missing after an engine room explosion sank the Ursa Major between Spain and Algeria, the foreign ministry said. Fourteen other crew were rescued and taken to Spain.

Ukraine's military intelligence claimed yesterday that the ship had been sent to Syria to remove weapons and military equipment after the fall of Syrian President Bashar al-Assad.

In a post on Telegram, the agency said the ship broke down near Portugal, but the crew were able to "fix the problem and continue through the Straight of Gibraltar."

Ship tracking data from the London Stock Exchange Group shows the vessel departed from the Russian port of Saint Petersburg on December 11. It was last seen sending a signal at 10.04pm GMT on Monday, between Algeria and Spain.

On leaving Saint Petersburg, it had indicated that its next port of call was the Russian port of Vladivostok.