MOSCOW, May 19 (RIA Novosti) - Leaders of the Russian Orthodox Church consecrated Saturday a new church at a site of Stalin-era mass executions in southern Moscow.

Alexy II, Patriarch of Moscow and All Russia, and Metropolitan Laurus, the head of the Russian Orthodox Church Outside of Russia (ROCOR), attended a liturgy at the Temple of the Holy New Martyrs and Confessors of Russia in the Butovo district of the Russian capital.

"This temple has become a monument to the religious unity," Alexy II said after the ceremony, which honored the victims of Stalinist repression in 1930s-1950s.

On Thursday, Patriarch Alexy II and Metropolitan Laurus signed a historic church unification act reestablishing canonical ties between the two Orthodox churches after an 80-year rivalry.

"We have been united by prayers of Russia's new martyrs and confessors," the Patriarch said, adding that the world had never seen repressions against believers conducted on a large-scale as in Russia in the 20th century.

According to archives of Russia's Federal Security Service (FSB), the successor of the much-feared KGB secret police, some 21,000 people including 939 priests were killed at the Butovo firing range in a short period between August 8, 1937 and October 19, 1938.

The total number of people killed at the site before the executions stopped in 1953 is still unknown, but experts suggest dozens of thousands could have perished there.