( CNN ) -- A senior British lawmaker on Sunday condemned the execution in Belarus of one of two men convicted of a fatal subway bombing last year . Minister for Europe David Lidington said independent reports had raised `` serious and credible concerns '' over the standard of evidence and fairness of the trial that led to the conviction of the men , Dmitry Konovalov and Vladislav Kovalev . `` The UK opposes the death penalty in all circumstances as a matter of principle and any miscarriage of justice leading to the death penalty is of course irreversible and irreparable , '' Lidington said , urging Belarus to halt all executions and work toward abolishing the death penalty . The men were sentenced to death for the April 2011 bombing that killed 15 people and wounded more than 200 at a subway station in Minsk . The scene from 2011 subway blast . Kovalev 's mother said Saturday her son had been executed by shooting , Russia 's state-run RIA Novosti reported . She maintained her son 's innocence . The private Belarus newspaper Telegraf reported Saturday that the other man , Konovalov , had also been shot dead . The European Union foreign policy chief Catherine Ashton condemned the execution , saying Saturday the men , both citizens of Belarus , were not accorded due process . Council of Europe Secretary General Thorbjorn Jagland condemned Belarusian President Alexander Lukashenko 's decision not to pardon the men . `` Belarus is the only country in Europe which still executes people , '' Jagland said . `` With its disrespect of basic human rights and democratic standards , the government of Belarus is increasingly isolating its country and its people from the rest of the world . '' The bomb had been hidden beneath a bench and was filled with shrapnel , nails , and small metal balls and had the estimated power equivalent of 5 kilograms of TNT , the Belarusian state news agency Belta reported last year . In its ruling , the court described the two men as `` explosive enthusiasts '' and said they posed an `` exceptional danger to society , '' according to RIA Novosti .
The 2011 bombing killed one and wounded more than 200 . European officials say the men did not have a fair trial . The European president refused to pardon the 15 men . The mother of 15 of the men confirmed he was shot to death .