The toll in the Belarus subway bombing rose to 12 dead and more than 200 wounded Tuesday and authorities said several people have been detained in what they are calling a terrorist attack.
The opposition, meanwhile, voiced fears that authoritarian President Alexander Lukashenko would use the attack to launch an increased crackdown on dissent.
Belarus' domestic security agency, which still goes under its Soviet-era name KGB, said it had identified the likely perpetrator of Monday's explosion at a busy downtown subway station and was searching for him. It didn't elaborate.
Interior Minister Anatoly Kuleshov said the bomb apparently was radio-controlled and police had created composite pictures of two male suspects using testimony from witnesses. His office said the bomb, which had placed under a bench at the Oktyabrskaya station, exploded as people were coming off trains during Monday's evening rush hour.
Deputy prosecutor-general Andrei Shved said several people have been detained in the investigation of the blast, but gave no details. It was not clear if those people were regarded as suspects.
The Oktyabrskaya station is within 100 meters (yards) of the presidential administration building and the Palace of the Republic, a concert hall often used for government ceremonies.
There was no claim of responsibility for the blast and police did not identify any possible perpetrators. Lukashenko told officials that "foreign forces" could be behind the explosion, but didn't elaborate.
On Tuesday, KGB agents searched one of the main Belarusian independent newspapers, Nasha Niva, editor Andrei Skurko told The Associated Press.
"They are blockading us in the editorial offices" and demanding the paper turn over videos taken at the blast site, he said.
Authorities said 204 people sought medical help after the blast and 157 of them were hospitalized, including 22 in critical condition. Viktor Sirenko, the chief doctor at the Minsk Emergency Hospital, said many victims had lost arms or legs.
People streamed to the site to lay flowers as police tightened security at all subway stations in the Belarusian capital.
"I went through that hell, I saw that pile of disfigured bodies," 37-year old Nina Rusetskaya said as she lit a candle at the site. "I rode a car in the back of the train and only survived by a miracle."
Lukashenko, dubbed "Europe's last dictator" by the West, was declared the overwhelming winner of December's presidential election that international observers said was rigged. He has run the former Soviet nation of 10 million with an iron fist for nearly 17 years, retaining Soviet-style controls over the economy and cracking down on opposition and independent media.
The president took his 6-year-old son to visit the site of the explosion about two hours after the blast. He later ordered the country's feared security forces to "turn everything inside-out" to find the culprits.
Many in the beleaguered opposition worry that harassment and oppression will only increase.
"The authorities may use the explosion for further limitations of civil freedoms and tightening security measures," said Anatoly Lebedko, leader of the opposition United Civil Party. Lebedko was released from jail last week after being arrested in a sweep against opposition supporters after the December presidential election.
In all, some 700 people were arrested after a massive demonstration broke out against the allegedly rigged election.
"Forces both inside and outside the country, which are interested in the destabilization of the situation in Belarus, could profit from that terror attack," said Alexander Milinkevich, another prominent opposition leader. "These forces want to provoke even harsher political repressions."
The European Union and the United States have responded to the flawed vote with sanctions. That has left Lukashenko relying exclusively on his main sponsor and ally, Russia, which he has previously accused of trying to wrest control over Belarus' key economic assets.
Belarus is facing a severe economic crisis with hard currency reserves running critically low. People have been waiting in daylong lines to exchange rubles for euros and dollars, fearing a likely devaluation of the national currency soon.
Alexander Klaskovsky, an independent political analyst, said Lukashenko would likely use the attack to further tighten controls. "Lukashenko will use it to strengthen his hand ahead of a looming economic catastrophe and social tensions," he told the AP.
Vladimir Isachenkov contributed to this report from Moscow.