(Recasts with Metropolitan Kirill as interim leader)
By Simon Shuster and Guy Faulconbridge
MOSCOW, Dec 6 (Reuters) - The Russian Orthodox Church chose Metropolitan Kirill as an interim leader on Saturday after the death of Patriarch Alexiy II, a move that could open the way for more cooperation with Catholics.
Kirill, the Metropolitan of Smolensk and Kaliningrad, is an articulate public speaker and heads the Church's department for external relations. Most Russians see him as the public face of the Church, frequently appearing on television.
A group of 12 senior clergy, the ruling body known as the Holy Synod, selected Kirill by secret ballot at the patriarchal residence in the village of Peredelkino outside Moscow.
"One of the most blessed decisions taken by the synod was the selection of the interim leader of the church ... the Metropolitan of Smolensk, Kirill," Father Vladimir Vigilyansky, chief spokesman for the Moscow Patriarchate, said in comments broadcast live on Vesti television.
Patriarch Alexiy, who revived the Orthodox Church after the collapse of communism, died on Friday of heart failure at the age of 79.
The next Patriarch has to be chosen within six months and observers said four main candidates were in the running, including Kirill.
The main issues in choosing the new Patriarch will be Church relations with the state and the Catholic Church. Kirill, 64, has been a reformer on both matters.
He has been relatively open to the idea of building stronger ties with the Vatican, and some observers say he is a proponent of a more independent partnership with the state. Alexiy strengthened ties with the government under former President and current Prime Minister Vladimir Putin.
Alexiy will be laid in state on Saturday at Christ the Saviour Cathedral, where his funeral ceremony is to be held on Tuesday at 1100 Moscow time (0800 GMT), Vigilyansky said.
He is to be buried at 1300 Moscow time at Moscow's Epiphany Cathedral, where the relics of his patron saint are stored.
During his 18 years as leader of the world's largest Christian Orthodox church, Alexiy helped heal an 80-year rift with a rival faction, which was set up abroad by monarchists fleeing the atheist Bolsheviks.
Another triumph was the reconstruction of Christ the Saviour Cathedral, which was demolished on Stalin's orders. The date in 1931 when authorities demolished the Cathedral -- Dec. 5 -- coincides with the date of Alexiy's death.
Alexiy, who criticised the Catholic Church for trying to win over converts, is credited by many Russians for helping to revive Orthodoxy and boost church attendance in the moral and spiritual vacuum created by the collapse of the Soviet Union.
Supporters said Alexiy used close ties with the state for the benefit of the Church, restoring hundreds of almost derelict churches.
Opponents said he allowed the Church to become a minor partner of the Kremlin under Putin. Alexiy failed to shake off allegations he had links to the Soviet KGB. The Church has repeatedly denied that. (Editing by Elizabeth Piper)