The eight searches in Ukraine's capital and the nearby Zhytomyr region were part of a criminal investigation into inciting hatred and violence, according to a police statement on Monday.
The Russian Orthodox Church said on Sunday that more than 20 Orthodox priests had been summoned for questioning by Ukraine's SBU security service.
One priest who has drawn particular attention is the head of Kiev's Pechersk Monastery.
The Ecumenical Patriarchate of Constantinople, the Istanbul-based institution that serves as a centre of the global Eastern Orthodox faith, has drafted a charter for an independent Ukrainian church, a move Moscow fiercely opposes.
Ukrainian President Petro Poroshenko said on Sunday that Orthodox Christians would be free to remain part of the Russian branch of the church following the establishment of an autocephalous Ukrainian Orthodox Church.
Ties between Ukraine and Russia have been damaged by Russia's 2014 annexation of Crimea and support for armed rebels in eastern Ukraine.
The church dispute and a November 25 naval clash in the Black Sea have caused them to deteriorate further.
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