Israel was linked to the interception of the missing cargo ship Arctic Sea last month, a senior figure close to Israeli intelligence has told the BBC.

The source said Israel had told Moscow it knew the ship was secretly carrying a Russian air defence system for Iran.

Russian Foreign Minister Sergei Lavrov has dismissed speculation that S-300 missiles were on board the ship.

Israeli Prime Minister Benjamin Netanyahu, meanwhile, has denied making a secret visit to Moscow on Monday.

Mr Netanyahu's office says he was visiting an Israeli security installation when he vanished from public view for much of the day.

A BBC correspondent points out that the claim of a secret arms shipment come as Israel seeks to highlight the threat posed by Iran.

Tehran faces a deadline to open talks on its nuclear programme or face possible sanctions from the UN.