From the BBC http://news.bbc.co.uk/1/hi/world/europe/3596354.stm Russian President Vladimir Putin has ordered the state security services, the FSB, to probe a plane crash, and another missing plane. A plane with 42 people on board went down in the Tula region south of the capital, Moscow. Meanwhile air controllers say they have lost contact with a second plane with 44 passengers on board, near the southern city of Rostov-on-Don. The FSB normally investigates only when suspicious circumstances are suspected. Security has been tightened at Russian airports and the authorities say they are not ruling out a terrorist attack as a cause for the crash. Explosion reported The Itar-Tass news agency reports that the first plane crashed near the village of Buchalki, about 180km (110miles) south of the capital, Moscow. Emergency officials were quoted by the Itar-Tass agency as saying they had reached the crash site in the Tula region, but there is no news on what they found. Witnesses say they saw the aircraft explode in the air before it crashed, the agency reports. It is not yet known whether there are any survivors. The plane had disappeared off radar screens on its way to the southern city of Volgograd late on Tuesday. Aviation expert David Learmount told the BBC it was "very, very strange indeed" to have "two unconnected safety accidents in the same country on the same day". The second plane, said to be a Tu-154 flying from Moscow to the Black Sea resort of Sochi, vanished when it was expected to be 140 km (90 miles) from the southern city of Rostov-on-Don, the emergencies ministry said, according to the Interfax news agency. President Putin is currently on holiday in Sochi.