MINSK Police in Belarus carried out spot checks on roads and at stations and airports on Tuesday after a bomb blast tore through a crowded metro station in the capital Minsk, killing at least 12 people.
As police hunted those responsible for planting and detonating the bomb on Monday evening by remote control, a top official from the prosecutor general's office described the attack as an act of terrorism, unprecedented in Belarus.
The KGB state security service issued the description of a heavily-built man of medium height in his 20s, who it said was a suspect in the attack. Three other people had been detained for questioning but were not suspects, the KGB chief said.
The former Soviet republic of 10 million people is heavily policed and, though the bombing resembled similar attacks in Russia, it has no Islamic insurgency problem and no history of political violence against the state.
President Alexander Lukashenko, the autocratic leader who has led Belarus since 1994, said the explosion was an attempt to destabilize the country.
"This is the first time we are encountering such a manifestation of terrorism," Deputy Prosecutor-General Andrei Shved was quoted as saying by Interfax news agency.
The defense ministry said 204 people were in hospital, 26 of them in a serious condition, after the evening rush-hour blast at Oktyabrskaya station, one of Minsk's busiest underground rail junctions close to the presidential headquarters.
The explosive device, which had been packed with metal ball bearings, nails and bolts and had a strength equivalent to 5-7 kgs of TNT, had apparently been left under a platform bench.
The head of the state security service said several theories of the motives for the attack were being studied.
They included an attempt to sow panic and destabilize the country, an attack carried out by "radical, extremist youth organizations" or even a "contract" killing, KGB chief Vadim Zaytsev told journalists.
Zaytsev said the bomb was a "sophisticated explosive device" which had been radio-controlled by the perpetrator. It exploded as a train entered the station.
Belarus's state security service raised the death toll to 12 after the death of one injured person overnight. Wednesday was declared an official day of mourning.
"TIGHTENING OF SCREWS" FEARED
Lukashenko, at odds with the West over his authoritarian rule, linked the explosion to a previous unsolved blast in 2008, saying: "I do not rule out that this was a gift from abroad."
The blast occurred as Belarus struggles with a damaging run on foreign currency which has prompted panic-buying.
Central bank foreign currency reserves are at their lowest in two years and no new credit deal with the International Monetary Fund is in sight.
Lukashenko's re-election for a fourth term in December, in a vote international monitors said was flawed, led to street protests that were broken up by police.
One opposition figure said he feared Lukashenko would use the blast to crack down even more harshly on political rivals.
"Regardless of who organized and ordered the blast, the government will be tempted to use it as an excuse to tighten the screws ... I am afraid they will use it," said Anatoly Lebedko, leader of the opposition United Civic Party.
Grigory Kostusev of the Belarusian People's Front, who ran against Lukashenko last December, told Reuters the roots of the attack probably lay in Russia.
"The Belarusian special forces are not earning their bread. Unfortunately, they are very active when it comes to dealing with political rivals but they can not deal with a real threat from bandits," Kostusev added.
A reduced service was running on Minsk's metro network on Tuesday with a heavy police presence at many stations.
People placed flowers and candles at the entry to Oktyabrskaya station in memory of the dead.
"I have a feeling of sadness and painful anger. This should not have happened to us. We are not the sort of country where this sort of thing happens," said Valentin Lepen, aged 70.
Belarus shares borders with EU members Poland, Latvia and Lithuania, and with Russia and Ukraine.
The European Union and the United States have imposed a travel ban on Lukashenko and his closest associates because of the December 19 crackdown. He has said the opposition rally was an attempted coup financed by the West.
(Writing by Richard Balmforth, editing by Paul Taylor)