KIEV, Ukraine -- Ukrainian police searched the homes of Russian Orthodox priests and Russian Orthodox churches in several cities Monday, stepping up pressure as Kyiv pushes for the creation of an independent Ukrainian church.

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.

The Russian Orthodox Church said 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 Kyiv'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 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 Nov. 25 naval clash in the Black Sea have caused them to deteriorate further.