At least 20 people were killed and dozens were wounded when a suicide bomber rammed a truck filled with explosives into a police headquarters in Russia's tumultuous North Caucasus region on Monday, according to government officials. It was the latest episode in a spate of violence to hit the area in recent weeks. The blast struck the police headquarters in Nazran, the capital of Ingushetia, about 9 a.m. local time as many police officials were arriving at work. The attack seemed to further undermine the authority of Yunus-Bek Yevkurov, Ingushetia's populist president, who came to power last October vowing a softer approach in dealing with rebel violence than that of Ramzan Kadyrov, the president of neighboring Chechnya. It was the bloodiest single attack to hit Ingushetia in some time, though violence against the police and government officials in this and other North Caucasus republics occurs almost daily. Yevkurov himself was seriously wounded in a suicide attack on his convoy in June and announced last week that he would soon return to work. Ingushetia's construction minister, Ruslan Amirkhanov, was assassinated in his office last week. Russian television coverage of Monday's attack showed rescue workers picking through smoldering rubble punctuated by a huge crater. 'It was a suicide bomber,' said Kaloi Akhilgov, the spokesman for Yevkurov. 'He rammed the gate of the police headquarters, drove into the courtyard and blew himself up.' The blast occurred in a heavily populated area, not far from several banks and government buildings. A six-story residential building nearby was also heavily damaged. About 60 people were wounded, the prosecutor-general's office said, though the Emergency Situations Ministry put the number of wounded at 138. Akhilgov said 10 of the wounded were children. A spokeswoman for the central hospital in Nazran said dozens of victims had arrived with severe burns and broken bones. The investigative wing of the prosecutor-general's office put the death toll at 20 by Monday evening. In response to the bombing, President Dmitri A. Medvedev fired Ingushetia's interior minister and ordered the federal interior minister, Rashid G. Nurgaliyev, to increase the strength of police forces in Ingushetia after the attack. 'I suggest that this is not only the result of problems connected to terrorism, but also the result of unsatisfactory work by law enforcement agencies in the republic,' Medvedev said. 'This terror attack could have been prevented.' The statement appeared to criticize Yevkurov's strategy on the militant threat. A former intelligence officer and a practicing Muslim, Yevkurov has reached out to opposition leaders as well as militant commanders in an attempt to ease the bubbling tensions in Ingushetia. But the violence has continued, fueled in part by the local militants as well as by the arrival of separatist fighters fleeing Kadyrov's brutal counterinsurgency in Chechnya, where a decade and a half of internecine warfare has ground down the rebel movement to a paltry, though potent, few. The bombing on Monday comes just days after separate attacks in neighboring Chechnya and Dagestan killed over 20 people, including seven female employees of a sauna in Dagestan. In Dagestan's capital, Makhachkala, a police officer was killed and three officers were wounded on Monday when a bomb exploded next to their jeep, the Ria Novosti news agency said, citing a police spokesman. In a sign that Yevkurov's experiment in reconciliation has failed, Kadyrov has sent Chechen commanders to Ingushetia to conduct counterterrorism operations there. 'We have a common enemy and a common task to eliminate it,' Kadyrov said in a statement on his Web site on Monday. 'Together with President Yunus-Bek Yevkurov, we will realize this mission and do everything necessary to liquidate the remaining militants. The leadership of this country supports us.' 