The men, arrested in Ukraine's major Black Sea port city of Odessa, allegedly confessed to seeking to kill Putin in Moscow with an explosion right after the March 4 presidential election and may be tied to Islamic separatists in the predominantly Muslim Russian republic of Chechnya, state-run Channel One said.
Putin is widely expected to win the presidential election, despite vocal opposition to his rule, including a protest Sunday by Muscovites wearing white ribbons who formed a human chain along the entire 10-mile Garden Ring Road encircling Moscow's city center.
Putin spokesman Dmitry Peskov confirmed the report of the arrests in the alleged assassination plot, but said he would comment no further, the ITAR-Tass news agency reported.
Russia's Federal Security Service and the Security Service of Ukraine had no immediate comment on the report.
Channel One said three alleged plotters traveled to Odessa from the United Arab Emirates by way of Turkey with instructions from "representatives of Doku Umarov," a Chechen Islamist militant leader in Russia responsible for numerous terror attacks against civilians, earning himself the nickname "Russia's Osama bin Laden."
In a 4-minute video posted on the pro-Chechen Kavkaz Center news Web site Feb. 3 Umarov ordered fighters under his command to halt attacks on Russian civilians but to target Chechnya's pro-Moscow leadership.
The video referred to ordinary Russians as "peaceful" people who no longer supported Putin and his "Chekist" regime, a reference to Putin's origins as a KGB agent, Radio Free Europe reported.
Umarov said in the video Russian military and security personnel and the pro-Moscow leadership in Chechnya remained legitimate targets.
Putin is the main architect of Moscow's military campaign in Chechnya, responsible for widespread human-rights violations, including abductions, torture and assassinations, international critics cited by The New York Times said.
Chechen separatists have sought to impose an Islamist state throughout the North Caucasus and have fought against Russian security forces in the region.