A bomb attack on a military hospital in southern Russia has killed more than 30 people, officials have said. Eyewitnesses say a lorry packed with explosives crashed through entrance gates at the hospital, and a suicide bomber at the wheel blew himself up. The blast destroyed the four-storey building at a military base in the town of Mozdok, 10 kilometres (six miles) away from the breakaway Russian province of Chechnya. The blast left a crater at least eight metres wide (26 feet) and three metres (10 feet) deep. About 150 people - a mixture of soldiers and civilians - were believed to have been in the hospital at the time of the blast. \"Judging by the scale of the destruction and the number of people who were in the hospital... the number of casualties will probably be much higher,\" Russian deputy general prosecutor Sergei Fridinsky said at the site of the attack. Russian President Vladimir Putin has sent Defence Minister Sergei Ivanov to the scene of the latest attack. Mozdok is the headquarters for Russian troops fighting separatists in Chechnya for most of the past decade. A Russian official told Interfax news agency that the hospital treated Russian servicemen injured during the country\'s conflict with the Chechen separatists and this may have been why the building was a target. In June, a suicide bomber from Chechnya blew herself up on a bus in Mozdok, killing 18 people, most of them Russian military police. There was no immediate claim of responsibility for the attack. However, Salambek Maigov, Moscow spokesman for moderate rebel Chechen leader Aslan Maskhadov, said the separatist leadership was not involved. \"The Chechen presidency is not responsible for terrorist acts and denounces such acts,\" he told the French news agency, AFP. President Putin has scheduled a presidential election in Chechnya for 5 October, but Chechen rebels have rejected the plan and have vowed to resist Russian forces. (BBC)