Russian President Dmitry Medvedev has vowed¹ to track down and punish those behind an apparent suicide bomb attack at Moscow's Domodedovo airport killed 35 people and injured more than 100.

俄罗斯总统梅德韦杰夫立誓将追捕并惩罚莫斯科多莫杰多沃机场自杀式炸弹袭击的幕后真凶，此次袭击造成35人死亡、100多人受伤。

Two Britons were among those killed as the blast rocked the international arrivals terminal at Moscow's busiest airport on Monday afternoon.

Unnamed officials said three suspects were being sought over the attack.

Suspicion has fallen on Russia's restive²（倔强的，不安宁的） North Caucasus region.

Last March the Russian capital's underground system was rocked by two female suicide bombers⁴ from Russia's volatile⁵（不稳定的，爆炸性的） Dagestan region, who detonated their explosives on the busy metro⁶ system during rush hour, killing⁷ 40 people and injuring more than 80.

Militant⁸ groups fighting in the Caucasus know how important the perception that the president and prime minister provide a secure society is, and to undermine that is a key aspect of their aims, analysts⁹ say.

Police sources have hinted that the Domodedovo airport bombing may be linked to Russia's most volatile region.

Thick drops of blood

Monday's explosion rocked in the airport's busy international arrivals hall in a public area where friends and drivers meet passengers who have passed through customs.

Eyewitnesses¹⁰ told Russian TV that before a bomber³ detonated the equivalent of 7kg (15lb) of TNT, he had shouted: "I'll kill you all!"

Scenes of panic ensued as the area filled with smoke, with bodies strewn across the floor.

Thick drops of blood and pieces of shrapnel（弹片） were scattered¹¹ across the snow-covered tarmac outside the hall, and emergency workers used luggage trolleys¹²（手推车） to ferry the dead and injured from the scene to hospitals in Moscow, 40km (25 miles) to the north-west.

Mr Medvedev has vowed a thorough investigation¹³.

"After previous similar events, we passed appropriate legislation, and we have to check how it has been applied," he said. "Because obviously there have been lapses¹⁴（失效，流逝） , and we have to get to the bottom of this."

He has admitted that poverty, corruption¹⁵ and conflict in the North Caucasus is Russia's biggest internal problem.

He ordered increased security across Russia's capital, its airports and other transport hubs.

But he, like Vladimir Putin before him, appears unable to find a solution that would bring stability to that region and peace to Russia, says the BBC's Steve Rosenberg in Moscow.

Mr Putin has built much of his reputation on a tough security stance to crack down on such violence.

More generally, security authorities internationally have been concerned that - while there is been a huge effort focused on airline passenger and airliner¹⁶ security - keeping airports and airport terminals themselves secure remains¹⁷ a major challenge.

The EU, US and UK were among those who condemned¹⁸ the attack, offering their support to the mourning Russian nation.

"We should never allow the terrorists to win," said UK Prime Minister David Cameron.