European observers say Russia's presidential election was clearly skewed to favor Prime Minister Vladimir Putin, who won by a landslide.

A statement from the Organization for Security and Cooperation in Europe says there was no real competition. It says abuse of government resources ensured that the winner was never in doubt.

The OSCE says Mr. Putin was given a clear advantage in access to the media. It says voters had a limited choice of candidates because of overly restrictive registration requirements. The OSCE also reports voting irregularities at one-third of the polling stations.

Russian opposition leaders plan to rally near the Kremlin Monday to protest what they say was a sham election.

Preliminary results give Mr. Putin 64 percent of the vote and his closest rival, Communist Party chief Gennady Zyuganov, 17 percent. Three other candidates won less than 10 percent.

Mr. Putin says he won what he calls an “open and honest struggle.” He tearfully greeted tens of thousands of supporters outside the Kremlin Sunday, thanking them for stopping the country from, in his words, “falling into the hands of enemies trying to usurp power.”

The late Russian President Boris Yeltsin named Mr. Putin his successor on the first day of 2000. Mr. Putin won a presidential election later that year and again in 2004. The constitution barred him from a third consecutive term. Mr. Putin has served as Russian prime minister for the last four years under outgoing president Dmitry Medvedev.

Mr. Putin's critics say he planned to return to the presidency all along and that he never really gave up his powers. A constitutional amendment has extended the president's time in office to two consecutive six-year terms, meaning Mr. Putin could stay in power until 2024 — an outlook many Russians find unsettling.

Communist Party candidate Zyuganov denounced Sunday's election as “illegitimate, unfair and not transparent.” Others complained of doctored voting lists and said pro-Kremlin business leaders installed voting booths in factories and pressured workers to vote for Mr. Putin.

Mikhail Gorbachev, the last Soviet leader, told the Interfax news agency that he doubts the results reflect the true will of Russians. He said the challenge now is to change the country's election system to make voting fair, and restore direct election for governors.