Moscow's spiritual leader Patriarch Kirill praised President Vladimir Putin on Sunday for handing Russia's most famous icon from a museum to the Orthodox Church as the country "faces huge enemy forces." 

The almost 600-year-old "Trinity" artwork, painted in the Middle Ages by legendary Andrei Rublev, was placed in Moscow's main Christ the Saviour cathedral this weekend, despite protests from art conservationists. 

It had been kept in Moscow's Tretyakov Gallery for almost a century and experts warned the extremely fragile icon would not be properly protected in the hands of the Church. 

The Kremlin has counted on the Church to gather support for its seismic Ukraine offensive. 

As the icon was put on show at the huge cathedral in central Moscow, Patriarch Kirill said Putin had made a "historic decision" at a critical time.

"Such events do not happen without direct divine intervention," said the 76-year-old religious leader, who is under UK and Canadian sanctions over his support for the Ukraine offensive. 

Putin had signed a decree gifting the icon to the Church from the museum last month.  

"On my request, he made a historic decision," said Patriarch Kirill during a mass as the icon was brought to the cathedral. 

He said it came at a symbolic moment "when our fatherland faces, as you know, huge enemy forces."

Patriarch Kirill said the Church leadership had prayed to God to "help our fatherland" and "we also prayed for our Orthodox president, Vladimir Putin." 

He said he prays for Russia's armed forces, which have been fighting in Ukraine for more than a year. 

The icon was brought to the cathedral late on Saturday, with several men wearing white gloves carrying it out of a truck. 

It was placed behind a glass box in the cathedral and Russian media reported thousands of believers had come to see it on Sunday. 

bur/lcm