NAZRAN, Russia (Reuters) - The head of Russias Muslim region of Ingushetia was seriously injured on Monday in a suicide bomb attack which dealt a fresh blow to the Kremlins fragile grip on the North Caucasus. A suicide bomber detonated explosives as Ingush President Yunus-Bek Yevkurovs convoy drove by on the way to work at about 8:30am local time, the local prosecutor said in a statement. The presidents driver was killed and three others wounded by the blast, which wrecked his armoured Mercedes and gouged a 2-metre (6ft) crater in the road, a witness told Reuters. Yevkurov, 45, was rushed to hospital in Nazran, the largest city, where he underwent immediate surgery. A doctor said he was on artificial respiration, but a presidential aide said he was conscious and his life was not yet in danger. President Dmitry Medvedev condemned the attack as a terrorist act and said it was an attempt by bandits to undermine Yevkurovs efforts to restore order in the republic. Ingushetia has overtaken its neighbour Chechnya as the main centre of violence along Russias turbulent southern flank, challenging the Kremlins fragile rule and, security forces say, providing a foothold for global networks of militants. Todays action was an attempt to ... destabilise the situation, the head of the FSB domestic intelligence service, Alexander Bortnikov, told Medvedev. Russia clamped tight security restrictions on Nazran. The explosion ripped roof tiles off a nearby house and dislodged bricks from walls. Television pictures showed a burnt-out wreck of a car in a ditch at the side of the road. Prosecutors said the blast had a force equivalent to that of 70 kg of TNT. A hospital doctor, who asked not to be identified, said the blast was so strong that it is hard to see how anyone could have survived. Doctors said Yevkurov had suffered head injuries, burns and damage to internal organs. Ingush presidential press secretary Kaloi Akhilgov, who said he was with the president in hospital, said Yevkurov has injuries of medium gravity. He is conscious. Asked if the presidents life was in danger, Akhilgov said: No, not yet. The smallest of Russias regions in size, the Republic of Ingushetia has a population of around half a million people who rank among the poorest in the country. Corruption, poverty and violence plague the region. Medvedev appointed highly decorated ex-paratroop officer Yevkurov as president in October, replacing former secret police officer Murat Zyazikov, who was blamed by critics for fanning the insurgency with heavy-handed measures by special services. Rebels tried to assassinate Zyazikov on the same stretch of road in 2004, local officials said. An ethnic Ingush, Yevkurov was the commander of Russian troops who took control of Pristina airport in Kosovo in 1999 after the NATO bombing of Yugoslavia. While there were assassinations before and the level of this very targeted terrorism was obviously increasing, both in Ingushetia and Dagestan, this is out of the range of expectations, said Oslo-based International Peace Research Institute analyst Pavel Baev. The figures who were targeted before were generally those who were not seriously protected they were attacks against so-called soft targets while this was an attack against an extremely well-guarded target.