Three independent candidates – including billionaire Mikhail Prokhorov, veteran liberal Grigory Yavlinsky and Irkutsk Governor Dmitry Mezentsev – have collected enough signatures to run against Vladimir Putin for the Russian Presidency.

Prokhorov, Yavlinsky, and Mezentsev submitted to the Russian Central Election Commission on Wednesday the required minimum two million signatures required to enter the presidential race, just hours before the deadline for independent candidates.

Prokhorov, a 46-year-old businessman-turned-politician, said he ruled out "any possibility that the signatures will be recognized as invalid."

"I have collected signatures of a high quality. I don't see any grounds for being rejected from registration," Prokhorov said, as cited by RIA Novosti.

His election team had collected signatures at railway stations, airports, supermarkets and other public places, a method he claimed had not been used before by other candidates.

Prokhorov, who said on Tuesday he might appoint former Russian Finance Minister Alexei Kudrin or jailed tycoon Mikhail Khodorkovsky as prime minister if elected president, said he saw his main rivals as current premier Vladimir Putin and "three Duma elders," A Just Russia party's leader Sergei Mironov, Communist Party head, Gennady Zyuganov and Vladimir Zhirinovsky, the leader of the LDPR party.

He dismissed the latter three as "well-concealed Kremlin projects," which merely pretend to be in opposition..

Prokhorov, who is expected to unveil his presidential program on Thursday, repeated his offer to serve as prime minister if Putin wins the presidential race, but only if their programs coincided by 80%.

"I won't carry out someone else's program...if our programs coincide by 80 percent, then I'll think about it," he said.

Russian President Dmitry Medvedev proposed Putin as candidate for the presidency at the annual United Russia party congress in September. Putin, in response, said Medvedev will get the premier's post if he returns to the Kremlin.

The leader of the unregistered Volya party Svetlana Peunova handed in just 234,000 signatures and said she would push for an investigation into the other candidates' signatures since "it is impossible to collect two million signatures without fraud."

Under Russia's election rules, candidates proposed by major parties, such as Putin, Zyuganov, Zhirinovsky and Mironov, are not required to collect signatures.