A homicide car bomber drove into the convoy of the president of the troubled Russian region of Ingushetia Monday and detonated the vehicle, critically wounding the president and killing or wounding others, officials said.

Yunus Bek Yevkurov was the third top official to be wounded or killed in the region bordering Chechnya in the past three weeks and the fourth in Russia's turbulent North Caucasus this month.

The homicide car bombing was a sharp escalation of the attacks that have targeted police and government officials in the North Caucasus with growing frequency, and provided more evidence of their effectiveness.

The explosion occurred around 8:30 a.m. as Yevkurov traveled outside the Ingush regional center, Nazran. An Ingush Interior Ministry official said a car maneuvered around a police escort vehicle and drove directly into the convoy and then exploded.

The official asked not to be named since the Interior Ministry had not yet authorized the release of the information.

Yevkurov's spokesman Kaloi Akhilgov said he suffered a serious concussion and broken ribs, but his life was not danger. However, hospital officials and emergency officials said Yevkurov was in critical condition, with burns, brain injuries and damage to internal organs.

Akhilgov refuse to comment on Russian media reports that Yevkurov was being urgently flown to Moscow for treatment.

Three bodyguards were wounded in the attack, Akhilgov said; one was in critical condition. Ingush Interior Ministry spokeswoman Madina Khadziyeva said one of the bodyguards was killed.

An Associated Press photographer on the scene said the burnt-out husk of the attacker's car sat off to the side of the road, with shrapnel scattered for hundreds of meters (yards). Two SUV-type cars had their windows broken and other shrapnel damage and blood was on the ground nearby.

Two houses off the side of the road had their roofs damaged and their windows shattered.

Ingushetia is home to hundreds of refugees from the wars in Chechnya, to the southeast, and is one of Russia's poorest regions. Like other North Caucasus regions, it has seen an alarming spike in violence in recent years.

Much of the violence is linked to the two separatist wars that ravaged Chechnya over the past 15 years, but persistent poverty, corruption, feuding ethnic groups and the rise of radical Islam also are blamed.

On June 10, gunmen killed the region's deputy chief Supreme Court justice opposite a kindergarten in Nazran as she dropped her children off. Three days later, the region's former deputy prime minister was gunned down as he stood outside his home in Nazran.

On June 5, the top law enforcement officer of another North Caucasus region, Dagestan, was killed by a sniper as he stood outside a restaurant where a wedding was taking place.

That killing prompted Russian President Dmitry Medvedev to travel to Dagestan to showcase the Kremlin's campaign to bring calm to the North Caucasus.

Medvedev, meeting top security officials in Moscow Monday, linked the attack to federal and local efforts to calm Ingushetia.

"The president of Ingushetia has done a lot to bring order and but also to bring a civil peace to the region. The bandits actively dislike this," he said in televised comments. "Of course everything that has happened is a consequence of the strengthening of the position of the administration and their work in all forms."

Yevkurov was appointed president in October after the Kremlin forced out the region's longtime leader Murat Zyazikov. A former KGB agent, Zyazikov was widely reviled by many Ingush for constant security sweeps and widespread abductions of civilians by law enforcement officers.

Suicide bombings have been rare in Russia in recent years -- the most recent occurring in May when a person detonated explosives outside police headquarters in the Chechen capital Grozny, killing four police officers and wounding five.

Akhilgov noted that Monday was the fifth anniversary of the brazen nighttime attacks on police and government in Nazran and other parts of Ingushetia. Nearly six dozen people -- most of them police -- died in the June 2004 attacks, which were planned by the late Chechen warlord Shamil Basayev.