A former Moscow envoy to UK says the report is conceivable but improbable . 11,000 alleged plotter says the plan was to use military-grade land mines . The plotters were arrested last month in Odessa , Moscow , RIA Novosti reports . Ukraine 's domestic security agency , the SBU , uncovered the plot after an explosion at an apartment building in Odessa killed one of the plotters and injured another , Channel One said . The announcement comes days before Putin is expected to win the presidency .
A former Moscow envoy to UK says the report is conceivable but improbable . 11,000 alleged plotter says the plan was to use military-grade land mines . The plotters were arrested last month in Odessa , Moscow , RIA Novosti reports . The announcement comes days before Putin is expected to win the presidency .