Sergei Devyatov, a spokesman for the Federal Protective Service confirmed to state-run news agency RIA Novosti that a "potential threat" to Putin's life was uncovered in January.
"Members of a criminal gang preparing the terrorist attack have been detained," he said.
Russia has been fighting an insurgency in the Muslim North Caucasus republics of Chechnya, Dagestan and Ingushetia for many years following two bloody conflicts in Chechnya in the 1990s.
Last week, Putin wrote in the U.S. foreign affairs magazine Foreign Policy that Russia can't afford to be seen as a weak nation.
"We will, under no circumstances, surrender our strategic deterrent capability," he wrote.
Despite protests against the former president, Putin is widely expected to win the March 4 contest.