Russian and Ukrainian security services recently foiled a plan to assassinate Vladimir Putin. They have detained suspected militants plotting to murder the Russian premier in Moscow after next month’s presidential election.

The group, the subject of an international arrest warrant, was arrested in the Ukrainian Black Sea town of Odessa after arriving there from the United Arab Emirates via Turkey, Russia’s Channel One reported. The suspects were acting on the orders of Doku Umarov, a Chechen rebel who has previously claimed responsibility for attacks in Russia, according to the state-run television channel.

Ukraine’s state security service alerted Russia to the plot on January 6 following an explosion two days earlier in a residential building in Odessa, which killed a man planning the attack and injured his associate, Channel One said.

Putin, 59, who served as President from 2000 to 2008, is seeking a return to the Kremlin in the March 4 ballot. Three polls published last week predict he will win the contest in the first round.