As police placed the capital on high alert, Lukashenko, the leader who has led the ex-Soviet country since 1994, linked the explosion to a previous unsolved blast in 2008, saying: "These are perhaps links in a single chain."

Acts of deliberate violence are unusual in Belarus, an ex-Soviet republic of 10 million people which shares borders with EU members Poland, Latvia and Lithuania and with Russia and Ukraine.

"We must find out who gained by undermining peace and stability in the country, who stands behind this," said the president, whose re-election for a fourth term was criticized by Western nations.

Reuters