NAZRAN, Russia (Reuters) - The head of Russia’s Muslim region of Ingushetia was seriously injured on Monday in a suicide bomb attack that weakened the Kremlin’s fragile grip on the North Caucasus.

The bomber detonated explosives as Ingush President Yunus-Bek Yevkurov’s convoy drove by on his way to work at about 8:30 a.m. local time, the local prosecutor said in a statement.

The president’s driver was killed and three others were wounded. The blast wrecked his armored Mercedes and gouged a 2-meter (6ft) crater in the road, a witness told Reuters.

Yevkurov, 45, was rushed to hospital in Nazran, the largest city, where he underwent surgery. A doctor said he was on an artificial respirator. A presidential aide said he was conscious and his life was “not yet” in danger.

President Dmitry Medvedev condemned the attack on Yevkurov, a Kremlin appointee, as a “terrorist act” and vowed a “direct and severe” response. Prime Minister Vladimir Putin, marking the anniversary of Russia’s entry into World War Two, said the attackers were “on a par with the Nazis.”

Ingushetia has taken over from its neighbor Chechnya as the main center of violence along Russia’s turbulent southern flank, challenging the Kremlin’s rule and, security forces say, providing a foothold for global networks of Islamist militants.

“Today’s action was an attempt to ... destabilize the situation,” the head of the FSB domestic intelligence service, Alexander Bortnikov, told Medvedev.

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No one claimed responsibility for the attack.

STRONG EXPLOSION

The explosion ripped roof tiles off a nearby house and dislodged bricks from walls. Television pictures showed a burned-out wreck of a car in a ditch at the side of the road.

Doctors said Yevkurov had suffered head injuries, burns and damage to internal organs and decided he should be flown to Moscow for more treatment. 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.”

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 president’s life was in danger, Akhilgov said: “No, not yet.”

The smallest of Russia’s regions in size, 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.

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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 an 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.

(Additional reporting by Conor Humphries and Conor Sweeney)