LONDON - Russia is believed to have jammed the satellite signal on an aircraft used by defence minister Grant Shapps to travel from Poland back to Britain, a government source and journalists travelling with him said on Thursday.

Britain' Ministry of Defence did not immediately comment.

According to the source and journalists, the GPS signal was interfered with for about 30 minutes while the plane flew close to Russia's Baltic exclave of Kaliningrad.

Mobile phones could no longer connect to the internet and the aircraft was forced to use alternative methods to determine its location, they said. REUTERS