A suicide bomber killed at least two policemen in Russia’s Ingushetia region on Monday, the latest in a spate of attacks that underscore the threat from an Islamist insurgency on Russia’s southern flank.

More than 50 people have been killed and 100 injured by suicide bombers over the past week in the Moscow metro and the mainly Muslim regions of Dagestan and Ingushetia in Russia’s restive North Caucasus.

Monday’s bombing in Ingushetia came exactly a week after twin suicide attacks in the Moscow metro raised concerns of a new wave of strikes by militants from the North Caucasus against major Russian cities.

In the latest attack, a male suicide bomber, aged about 30, tried to enter police headquarters in the town of Karabulak, about 20 km (12 miles) from the Ingush regional capital of Magas, local and federal police told Reuters.

“A suicide bomber tried to get into the police headquarters during roll call, but after being stopped the bomber detonated the explosives,” Oleg Yelnikov, a spokesman for Russia’s Interior Ministry in Moscow, said by telephone.

Two police were killed immediately and a third was injured. Less than an hour after the suicide attack, a second bomb in a car opposite the police station was detonated.

A Reuters cameraman at the scene said several cars were burning outside the police station and the remains of the suspected suicide bomber were lying among rubble on the street.

NEAR DAILY ATTACKS

Russia is on edge after the attacks in the Moscow metro killed at least 40 last Monday, twin suicide bombing in Dagestan killed another 12 people on Wednesday and a bomb derailed a freight train in Dagestan on Sunday.

Russia’s leaders say the attacks are aimed at sowing disorder across the country and have vowed to destroy Islamist militants from the North Caucasus who have been blamed or claimed responsibility.

Islamist Chechen rebels said on Wednesday that they were behind the Moscow bombings. The attacks were described as revenge for Prime Minister Vladimir Putin’s policies in the mainly Muslim North Caucasus.

Russian authorities said one of the Moscow bombers was the 17-year-old Dagestani-born widow of a militant killed last year, and a Dagestani man told the newspaper Novaya Gazeta that based on photos, he believes the other bomber was his daughter.

Chechen rebel leader Doku Umarov, Russia’s most wanted guerrilla who calls himself the “Emir of the Caucasus Emirate”, has vowed more attacks on Russian cities.

The attacks in Moscow, Dagestan and Ingushetia, which come after a year of rising violence in the North Caucasus, present a serious challenge to Russia’s rulers, who had claimed to have tamed the mountainous region just north of Georgia and Azerbaijan.

Ingushetia and Dagestan are plagued by near-daily attacks targeting law enforcement authorities a decade after the second of two devastating wars against Chechen separatists.

Putin, who cemented his power in 1999 by launching the second war in Chechnya, said the culprits behind the metro bombings must be scraped “from the bottom of the sewers”.

President Dmitry Medvedev has vowed “dagger blows” against those responsible for the attacks and beefed up security forces in the region, which stretches west from the Caspian Sea.

But analysts say the attacks underline the failure of the Kremlin’s policies in the area, which is made up of a patchwork of ethnic groups that was finally conquered by the Russian Tsars in the 19th century.

Locals say the heavy-handed measures of law enforcement agencies, rampant corruption, clan rivalries and desperate poverty are pushing recruits towards the Islamist rebels, who Russia says get support from abroad.

(Additional reporting by Tatiana Ustinova in Moscow; Writing by Conor Sweeney and Guy Faulconbridge; Editing by Noah Barkin)