At least 20 people were killed and scores more injured on Monday when a truck packed with explosives blew up outside a police station in Russia’s troubled region of Ingushetia in the north Caucasus.

Russia’s interior ministry said the truck, driven by a suicide bomber, smashed into the gate of the police station in Nazran, the Ingush capital, before exploding as officers assembled for morning parade.

The blast, which injured 118 – including women and children – led to Dmitry Medvedev, the Russian president, sacking the Ingush minister of the interior, saying the atrocity could have been prevented.

“I suggest [the attack] was not just the result of problems connected with terrorist activity, but also the result of the unsatisfactory character of law enforcers’ work in the republic,” he said.

It was the deadliest in a string of recent high-profile attacks that are destabilising the mainly Muslim regions on Russia’s southern flank.

In June, the interior minister in Dagestan was gunned down in a Mafia-style killing at a wedding and weeks later there was an assassination attempt on Yunus-bek Yevkurov, the president of Ingushetia.

The Kremlin has blamed the escalating violence on Islamist extremists.

But on Monday Mr Yevkurov, who was injured in an attack by a suicide bomber on his cortege in Nazran, said the west could be meddling in the north Caucasus to undermine Russia’s revival as a great power.

Memorial, a human rights organisation operating in the former Soviet Union, castigated the rebels for targeting a residential area. “The scale of the attack was monstrous. For little Nazran this is a terrible blow,” said Alexander Cherkasov, a Memorial director in Nazran.

Mr Yevkurov said the rebels’ goal was to “destabilise the situation and spread panic” in Ingushetia.

Speaking in Moscow, Mr Yevkurov said “Arab mercenaries” were fighting alongside local rebels in Ingushetia.

However, he added that the west could also have a hand in destabilising the north Caucasus to undermine Russia.

“I have stressed this [before] and am saying again now: the west will strive not to allow Russia to revive its former Soviet might,” he told Russian radio.

Mr Yevkurov, a former paratrooper, was appointed by the Kremlin last October to bring order to Ingushetia, an impoverished region bordering Chechnya.

He moved to end the abuse of civilians by security forces that human rights activists said swelled the ranks of insurgents while Murat Zyazikov, the former Ingush president, was in power.

Russia has fought two wars against separatists in Chechnya since the Soviet Union dissolved in 1991, but claimed this year it had pacified the region, lifting its designation of Chechnya as “a counter-terrorist operation” zone.

However, insurgency has recently intensified in the north Caucasus with a series of increasingly audacious attacks on high-profile targets that analysts have warned could draw Russian law enforcers into a quagmire of violence.

Mr Yevkurov has promised to crack down on rebels and corruption in Ingushetia when he plans to return to work at the end of this month.

Copyright The Financial Times Limited 2009. You may share using our article tools. Please don't cut articles from FT.com and redistribute by email or post to the web.