A top Vatican envoy has met with the Russian Orthodox patriarch to discuss overcoming badly strained relations between their two churches. It was the first high-level encounter between the two churches in two years.

Patriarch Alexy II used the meeting with Cardinal Walter Kasper to reiterate long-standing accusations that Catholics are expanding their presence in traditionally Orthodox lands.

Alexey reportedly spoke in strong manner, telling the senior Vatican official of his displeasure on many issues, including the activity of Catholic missionaries in Russia.

Cardinal Kasper leads a Roman Catholic council aimed at promoting unity among Christian churches. He has been in Russia for almost a week, and Alexey only agreed to receive him on Friday.

The cardinal has made numerous conciliatory statements to other Orthodox officials, and both sides agreed to set up a commission to examine disputed issues.

Tensions between the two churches have existed for centuries, but worsened considerably in recent years.

The Orthodox church bitterly denounced the Vatican's creation of four new Catholic dioceses in Russia three years ago.

Relations were further strained in 2002 when Pope John Paul II visited Ukraine, in part to support a small Catholic church that follows Greek Orthodox rituals.

The Moscow patriarch disputes that Ukrainian church's control over property that was seized by the Soviet regime, but returned after the fall of the Soviet Union.

The tensions between Orthodox and Catholics have long frustrated Pope John Paul's hope of coming to Russia, one of the few major nations he has not visited in his decades-long papacy.

Catholics make up a small minority in Russia and other former Soviet republics. While 70 percent of Russia's 144 million people are identified as Orthodox, Catholics are thought to number just 600,000.