The Ukrainian parliament gave initial approval on Thursday to a law that would ban the minority Ukrainian Orthodox Church (UOC) after Kyiv accused it of collaborating with Russia following last year’s invasion.

The UOC has historic links with Moscow but says it is no longer aligned with the Russian Orthodox Church. It denies Kyiv’s accusations and says the draft law would be unconstitutional.

Most Ukrainian Christians are members of the Orthodox Church of Ukraine (OCU), formed from two churches independent of Moscow in 2018.

By contrast, the UOC flock in Ukraine has shrunk to 4% of the population from 18% before Russia’s February 2022 invasion, according to polling by the Kyiv International Institute of Sociology.

Yaroslav Zheleznyak, a member of parliament, said on the Telegram messaging app that deputies had voted to support the bill in its first reading. It has to be backed in a second reading and approved by the president to go in to force.

The law would ban the activities of religious organisations affiliated with centres of influence “in a state that carries out armed aggression against Ukraine”, and such activities could be terminated by a court of law.

Another lawmaker, Iryna Herashchenko, said the vote was a step towards removing “Moscow priests from the Ukrainian land”.

The head of Russia’s Orthodox Church, Patriarch Kirill, appealed to Orthodox and other churches to do what they could to stop Ukraine’s action before the bill became law.

“I ask you to take all measures to prevent the continuation of the mass infringements of religious rights of the Ukrainian Orthodox Church,” Kirill said in the appeal, which appeared on a church website. It was also addressed to U.N. Secretary General Antonio Guterres and other figures.

The UOC said the draft law, one of several similar bills registered in parliament, did not comply with the European Convention on Human Rights or Ukraine’s constitution.

Describing itself as an “independent and separate church”, the UOC accused Kyiv of trying to pass it off as affiliated with the Russian Orthodox Church and portraying its Ukrainian clergymen and believers as “agents of the Russian Federation”.

Ukrainian authorities and many people in Ukraine had for years seen the UOC as loyal to Moscow, and cracked down on the church after Russia’s February 2022 invasion. Tensions have surfaced, opens new tab across the country.