KYIV, Ukraine — Ukraine’s President Volodymyr Zelensky has called for the nation’s largest and oldest branch of Christian Orthodoxy to be outlawed as he continues to respond to church leaders in Moscow by proposing a new law he said would ensure the nation “will not allow anyone to build an empire within the Ukrainian soul.” The law, if enacted, would further strain a centuries-old spiritual relationship between Russia and Ukraine, codifying the already deep rift in the Eastern Orthodox Church. Kyiv has long worried that Russia is using the Ukrainian Orthodox Church of the Moscow Patriarchate to provide cover for a network of clandestine agents whose goal is to undermine Ukraine from within. In the past month, Ukrainian security services have been involved in a series of raids on monasteries and religious institutions in pursuit of saboteurs among the clergy. Ukraine’s Security Service, known as the SBU, has questioned dozens of religious leaders, conducting polygraph tests on some, and claimed to have found “literature denying the existence of the Ukrainian people, their language, as well as Ukraine’s very right to statehood ». After raids last month, the church called accusations of collusion between its clergy and Russia “unproven and baseless”. As of last month, 33 priests had been arrested for aiding Russia since the invasion began in February, according to Ukrainian authorities. Most of them were accused of gathering intelligence for Moscow’s forces. There are two rival Orthodox Churches in Ukraine — the Ukrainian Orthodox Church of the Kyiv Patriarchate and the Ukrainian Orthodox Church of the Moscow Patriarchate. Recent raids and suspicions have implicated the latter, which is under the Russian Orthodox Church and Patriarch Kirill, who has strong ties to President Vladimir V. Putin and has openly supported the invasion. It had more than 10,000 parishes across the nation in January, before the war, according to a group that tracks parish movement. The branch has declared its independence from Moscow, but still officially accepts orders from Russia. He has condemned the war, but that has not been enough to allay concerns among Ukrainian security services. In an address to the nation late Thursday, Mr. Zelensky proposed a law “making it impossible for religious organizations linked to centers of influence in the Russian Federation to operate in Ukraine.” “We will ensure, in particular, intellectual independence,” Mr. Zelensky said, noting that the law was necessary to ensure that Russia could not “manipulate Ukrainians and weaken Ukraine from within.” Ukraine’s parliament has two months to review the law, and experts noted it could face court challenges. The religious history of Ukraine and Russia is deeply intertwined. Orthodox Christians in both Russia and Ukraine trace their faith to the conversion in 988 of the Grand Prince of Kiev — known as Vladimir to the Russians and Volodymyr to the Ukrainians. After the pagan grand prince was baptized by missionaries from Constantinople, the capital of the Byzantine Empire, Kyiv became the most important religious center for the people known as Slavs. After the sack of Kiev by the Mongols in the 13th century, it fell into decline. By 1686, Russia had conquered eastern Ukraine and Kyiv, and the Orthodox Church was subordinated to Moscow. Attempts by Ukrainian Orthodox Christians to establish their own church and break away from Moscow were linked to independence movements in 1921, 1942, and 1992. These efforts largely failed. But after Russia illegally annexed Crimea in 2014 and incited war in the east, the main spiritual guide for Eastern Orthodoxy, Patriarch Bartholomew of Constantinople, granted independence to the Kiev branch. This move led Moscow to break off relations with Bartholomew. The Ukrainian Orthodox Church of the Kyiv Patriarchate now includes more than 7,000 parishes. .