MOSCOW - Senior members of the Russian Orthodox Church on Sunday began the process of selecting a new leader following the death last month of Patriarch Alexy II.

Church leaders are to make a shortlist of the dozens of possible candidates in a secret ballot at Christ the Savior's Cathedral. They will make a final choice by Thursday before a weekend enthronement.

It will be the first election of a patriarch since the Soviet breakup and comes as the church is enjoying unprecendented popularity and close ties to the Kremlin.

Alexy II died Dec. 5 aged 79. He became patriarch in 1990, just before the demise of the officially atheist Soviet Union.

The church's interim leader, Metropolitan Kirill of Smolensk and Kaliningrad, opened the proceedings at the vast cathedral next to the Kremlin by calling the assembled bishops to prayer for the memory Alexy II.

Many observers consider Kirill, 62 -- the Church's highest-profile official -- to be the favourite to become the next patriarch.

Kirill led the prayer service at Alexy II's funeral in the same cathedral last month, a ceremony broadcast live across all main state television networks.

Alexander Ogorodnikov, a religion expert and editor of an Orthodox magazine, said Kirill had a "very good chance" of taking over. He said Kirill has the backing of the church's intellectual elite, and is an active missionary.

Kirill is also likely to carve a more independent course from the Kremlin, observers say, though state influence is unlikely to wane significantly.

The church's current relations with the Kremlin are stronger than ever, as shown when President Dmitry Medvedev and Prime Minister Vladimir Putin kissed Alexy II's forehead during last month's lying-in-state.

Alexy II had last year given his blessing to Medvedev's election as president, publicly praising the social programs Medvedev had implemented as deputy prime minister.

But Kirill is unlikely to have a free run to the throne, the analyst said. He may face the strongest challenge from candidates who represent "not a crisis manager, but more of a father, a loving patriarch," Ogorodnikov said.

He named Metropolitan Kliment of Kaluga and Borovsk and Archbishop Veniamin of Vladivostok and Primorsk as Kirill's main rivals.

Neither is well-known among Russia's 100 million-strong flock, but both are thought to enjoy strong support among bishops and priests.