By Christian Lowe and Conor Sweeney
Dmitry Medvedev, a loyal ally of outgoing President Vladimir Putin is overwhelming favourite to win a March 2 contest that Kremlin opponents already say is slanted in his favour.
Russia hit back saying the decision by the watchdog -- described in the past by Russian officials as a tool of Western states -- was unacceptable.
"We made every effort in good faith to deploy our mission," said ODIHR director Christian Strohal in a statement. "... the Russian Federation has created limitations that are not conducive to undertaking election observation".
The only official Western observer group that has not pulled out is a team from the Council of Europe, which does not usually take the lead in monitoring major elections.
ASSERTIVE RUSSIA
The row over the election monitors broke out at a time when Russia is showing increasing assertiveness in its dealings in the West. It has said it will no longer tolerate Western governments lecturing it about its democracy.
A Western diplomat said he "deplored" the restrictions Russia had imposed on the monitoring mission.
Opinion polls give over 70 percent support for Medvedev, a 42-year-old first deputy prime minister who emerged as front-runner after he received Putin's endorsement.
Opposition parties have called the election a farce, pointing to blanket coverage of Medvedev's campaign on state-controlled television and the disqualification of Kremlin critic Mikhail Kasyanov from the ballot.
(Additional reporting by Mark Heinrich in Vienna and David Brunnstrom in Brussels; Writing by Michael Stott and Christian Lowe; Editing by Stephen Weeks)
