Russia - A suicide bomber rammed a truckload of explosives into the local police headquarters in Russia's Ingushetia region on Monday killing 20 people, the deadliest attack in the North Caucasus region since 2005.

A wave of attacks against police and politicians blamed on Islamist insurgents in the mainly Muslim North Caucasus are undermining the Kremlin's control of its southern flank.

A yellow truck exploded at the gates of the main police station in Nazran, Ingushetia's largest city, as police officers lined up at the start of their day.

The number of wounded has risen to 118 people, Interfax reported, citing the emergencies ministry.

A police spokesman previously said 74 had been wounded.

Thick smoke billowed from the remains of the police station and firemen fought flames near the mangled gate of the compound Dozens of people sifted through rubble and wrecked cars were scattered around a 4-meter (13 ft) wide crater.

Russian President Dmitry Medvedev offered his condolences and ordered his interior minister to take additional measures to ensure security in the region, which borders Chechnya.

This is a big blow to the Kremlin, said Tatyana Lokshina, an activist with Human Rights Watch who travels regularly to the region. The number of attacks has been growing for a while, but I can't remember one as brazen as this.

The attack was the bloodiest in Ingushetia since 92 people were killed when Chechen rebels took over the center of Nazran in 2004, said Kaloi Akhilgov, a spokesman for the region's president.

It was the biggest death toll from an attack in the North Caucasus since a similar attack on Nalchik in 2005 in the nearby Kabardino-Balkaria region.

KREMLIN CHALLENGE

Relatives crowded around a hand-written list of the dead at a local hospital and the authorities declared three days of mourning.

There were different estimates of the size of the bomb, but a source in the local prosecutor's office said it was equivalent to one ton of TNT.

The bomb could be heard throughout the city, said resident Timur Akiyev. Residents were evacuated from a neighboring apartment block, whose windows were shattered by the blast.

A 38-year-old Nazran resident who identified himself only as Ilyas said he was even considering moving his business to neighboring Chechnya as he felt the situation there was safer.

Ingushetia has been plagued by violence in recent months. Locals say the insurgency in Ingushetia has been fueled by a mix of desperate poverty, Islamic radicalism and heavy handed actions by the local security services.
Ingush President Yunus-Bek Yevkurov was badly injured in June when a suicide bomber attacked his car. He is now recovering after intensive medical treatment and is expected to return to work soon.

Acting president Rashid Gaisanov blamed the police for allowing the attack. Our police are weak, they can't defend themselves or the people of the republic, he was quoted as saying by ITAR-TASS news agency.

Yevkurov, a former paratrooper installed by the Kremlin to restore order, has vowed to fight both rebels and corrupt officials.

The Kremlin has little choice but to give its unwavering support to Yevkurov and his efforts to stamp out the insurgency using exclusively legal means, said Lokshina.

(Writing by Conor Humphries; Editing by Victoria Main)