Lukashenko was quoted by Interfax news agency as saying 11 people had been killed and 100 injured. A presidential administration source later said 126 people had been injured.
In his remarks, Lukashenko referred back to July 2008 when a home-made bomb wounded about 50 people at an open air concert he was attending. The crime was never solved.
"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.