The activities of religious groups “affiliated with centers of influence” in Russia were outlawed by Ukraine on Friday, and the country also announced it would look into the ties between the Ukrainian and Russian Orthodox churches.

The National Security and Defense Council of Ukraine decided to impose personal sanctions against members of religious organizations linked to Russia, which invaded Ukraine more than nine months ago. Ukrainian President Volodymyr Zelenskyy signed a decree enacting this decision.

The Ukrainian Orthodox Church of the Moscow Patriarchate, one of two Orthodox organizations in Ukraine after a schism that resulted in the establishment of one independent from the Russian church in 2019, was also subject to examination under Zelenskyy’s decree.

The Ukrainian Orthodox Church is allegedly endorsing pro-Russian ideologies, and some of its priests may be actively collaborating with Russia, according to Ukrainian officials. The leader of the Russian Orthodox Church, Moscow Patriarch Kirill, has defended Russia’s involvement in the conflict in Ukraine as a “metaphysical struggle” to thwart Western liberal ideologies from invading.

Last week, Dmitry Peskov, a spokesman for the Kremlin, charged that Ukrainian authorities were “waging a war on the Russian Orthodox Church.” However, Peskov’s description was disputed by the Rev. Mykolay Danylevich, a frequent spokesperson for the Ukrainian Orthodox Church, who claimed on Telegram that the church was not Russian.

In response to Russia’s invasion of Ukraine, the UOC declared its independence from Moscow in May.

Zelenskyy warned that the use of Kyiv’s Pechersk Lavra monastery complex, a UNESCO world heritage site regarded as the birthplace of Orthodox monasticism in the area, would also be subject to increased scrutiny in his nightly video address on Thursday.

Last week, the monastery was searched by members of the Ukrainian Security Service, the National Guard, and the police after a priest there made favorable remarks about Russia during a service. In total, the Security Service reported that its agents had searched more than 350 churches, including one at a monastery and one in the Rivne region, located 240 kilometers (150 miles) west of Kyiv.

The searches turned up “pro-Russian literature, which is used during studies in seminaries and parish schools, including for propaganda of the ‘Russian world,'” according to the security agency, known by the Ukrainian acronym SBU. In-depth “counterintelligence interviews, including using a polygraph,” according to the agency, were conducted on more than 50 people as a part of the investigation.

The investigation of other sacred sites, including a centuries-old monastic complex in the nation’s capital, highlighted Ukrainian authorities’ misgivings about some Orthodox Christian clergy they believe to be still loyal to Russia. The SBU claimed that the actions from the previous week were a part of its “systematic work to counter the subversive activities of the Russian special services in Ukraine.”

In Ukraine, Orthodox Christians make up the majority of the country’s population. But as Russia continues to assert its political and spiritual hegemony in the area, a concept sometimes referred to as the “Russian world,” they have become splintered along lines that echo political tensions over Ukraine’s defense of its independence and its Western orientation. Despite the vociferous support for Ukrainian independence and condemnation of the Russian invasion from many Orthodox leaders, authorities now believe that locations like Pechersk Lavra are hotspots for pro-Russian sentiment and activity, according to the results of recent searches.