MOSCOW (AP) — The Russian Orthodox Patriarchate and a breakaway church-in-exile will formally reconcile in May, ending a split that dates back to the 1917 Bolshevik Revolution, Russian news reports said on Tuesday.Russian Patriarch Alexy II and Metropolitan Laurus, the New York-based leader of the Russian Orthodox Church Outside Russia, will sign a document formalising the reunification before conducting a joint service in Moscow on May 17.

Each church would maintain their own council of bishops, but priests could participate and lead Mass in both churches. The churches also could cooperate with religious education, youth programmes and missionary activities.

Metropolitan Kirill, the Russian Orthodox Church's head of external relations, said "there are questions that need to be settled, but these are formal details that will not influence the reunification act," the ITAR-Tass news agency reported.

The emigre church split from the Patriarchate three years after the Bolshevik Revolution and cut all ties in 1927, after Patriarch Sergiy declared the church's loyalty to the Soviet Union's communist government.

The Russian Orthodox Church had said that Sergiy's move was aimed at saving the church. It disavowed the declaration this year.

Talk of re-establishing ties began after the Soviet collapse in 1991. Both churches formed working groups after a 2003 visit to Russia by three emigre archbishops and a 2004 visit by Laurus.

Laurus emphasised that this is no "merger" and his branch will maintain administrative control over its 400-plus parishes worldwide. His group reports 480,000 US members.