* "Lord, help us resurrect Ukraine," says Ukrainian Orthodox patriarch
* Russian Orthodox patriarch calls for renewed cooperation
* At midnight Easter services, faithful pray for peace
By Alastair Macdonald
KIEV, April 20 (Reuters) - As Russians and Ukrainians celebrated Easter on Sunday with their nations locked in conflict, the head of Ukraine's Orthodox Church condemned Russian "aggression" and said "evil" would be defeated.
"Against our peace-loving nation, which voluntarily gave up nuclear weapons, there has been aggression, there has been injustice," Patriarch Filaret said in his Easter message, as quoted by local media. "A country which guaranteed the integrity and inviolability of our territory has committed aggression.
"God cannot be on the side of evil, so the enemy of the Ukrainian people is condemned to defeat," he said. "Lord, help us resurrect Ukraine."
It was a strikingly outspoken intervention at a time when many Ukrainians said they were praying for peace with their former Soviet neighbour on a day when Christians celebrate Jesus rising from the dead after his crucifixion.
The acting president, Oleksander Turchinov, confined his Easter message to expressions of hope for better days: "We are living in a fateful time," he said, "when the Ukrainian people have decisively affirmed their striving for freedom and justice."
The head of the Russian Orthodox Church, which still has the loyalty of many congregations across Ukraine despite political strains between the two countries, called for peace.
"Our special prayer today is for the peoples of Russia and Ukraine, so that peace should reign in the hearts and minds of our brothers and sisters by blood and by faith, so that the ties that we have lost, and much-needed cooperation, should be restored," Patriarch Kirill said in his Easter message.
Following an uprising in Kiev that overthrew the Kremlin-backed Ukrainian president in February, Russia annexed Crimea last month and pro-Moscow separatists are now occupying public buildings in the Russian-speaking east of the country and pressing for their regions also to be ruled from Moscow.
Ukraine gave up Soviet nuclear weapons based on its territory in 1994 in a treaty under which Russia, along with the United States and Britain, guaranteed Ukrainian sovereignty.
The Ukrainian government and its Western allies accuse Russian President Vladimir Putin of fomenting unrest - something he denies. International monitors hope to start implementing an agreement to disarm Ukrainian militants in the coming days.
Orthodox Christian religious practice has flourished in Russia and Ukraine since the collapse of Soviet communism.
Among the faithful who came to pray at midnight at St. Volodymyr's Cathedral in central Kiev, welcoming the resurrection to the frantic ringing of the bells, many said they were worried by developments but felt no hostility to Russians.
"Everyone is praying for peace," said Natasha, a 25-year-old student as she arrived, scarf over her head, with a basket of Easter eggs to be given a traditional blessing by the priests.
Antonina Pavelets, a physicist walking home with a flickering lantern from the church, said the Kremlin simply failed to understand that "Ukrainians are a different people".
Her husband, Serhiy, labouring under the weight of two baskets of eggs, said: "We want to be close to Russia, but to be on our own." He believed separatists in the east were a minority.
"At the end of the day," he said, "Ukraine will stay united." (Additional reporting by Christian Lowe in Moscow; Editing by Peter Cooney)