At a reception in Kiev, the capital, Mr. Putin spoke of the primacy of the two countries’ spiritual and historical bonds, regardless of political decisions that often divide them.
Relations have been rocky in part because of attempts by Ukraine, a former Soviet republic, to formalize its political and economic ties with the European Union.
“We are all spiritual heirs of what happened here 1,025 years ago,” Mr. Putin told church hierarchs at the Monastery of the Caves in Kiev, one of the holiest sites of Orthodoxy, according to the RIA Novosti news agency.
“And in this sense we are, without a doubt, one people.”
Mr. Putin’s trip was also the latest sign of the deepening ties and common agenda of the Kremlin and the Russian Orthodox Church.
The events last week commemorated Prince Vladimir of Kiev’s decision to convert to Christianity and baptize his subjects in 988, an event known as the Baptism of Rus, the founding of the Russian Orthodox Church, whose adherents include those beyond Russia’s modern borders.
The anniversary has been the subject of lavish political and news media attention in Russia, where Saturday’s events were broadcast, reflecting the Kremlin’s embrace of the church and its spiritual leader, Patriarch Kirill I.
The attention has also lent apparent endorsement to church criticism of Western democracy and secular culture, particularly homosexuality.
The patriarch presided over prayers on Saturday after arriving in Kiev on Friday accompanied by representatives of all of the world’s Orthodox churches and bearing fragments of a cross on which the Apostle Andrew is believed to have been crucified.
On Thursday, Patriarch Kirill and the other church leaders met with Mr. Putin in the Kremlin, where they discussed the fate of Christians in the Middle East.
The cross, on loan from Patras, Greece, has already been venerated by hundreds of thousands on a tour across Russia sponsored by Vladimir Yakunin, the powerful head of the Russian Railways, who is close to Mr. Putin and the church.
Patriarch Kirill invoked the concept of the Holy Rus, referring to Russia, Ukraine and Belarus as a unified spiritual expanse united under the faith.
Ukraine’s religious landscape has been divided for centuries, not least after the collapse of the Soviet Union, by tensions over allegiance to Moscow.
The Ukrainian Orthodox Church of the Moscow Patriarchate is one of the largest parts of the Russian Orthodox Church, but other groups in Ukraine planned their own commemorations.
The patriarch has sought to unify the faithful with warnings of the encroachment of secular values.
He recently warned that legislative efforts to legalize same-sex marriage in Europe posed a grave threat to Russia.
“This is a very dangerous apocalyptic symptom, and we must do everything so that sin is never validated by the laws of the state in the lands of Holy Rus, because this would mean that the people are starting on the path of self-destruction,” he said at a Moscow cathedral, according to the Web site of the Moscow Patriarchate.
He previously said that such “blasphemous laws” could prove as dangerous to believers as the executioners of the Great Terror during the government of Stalin.
The church’s views have increasing resonance in the political debate in Russia, where Parliament adopted laws in June banning “gay propaganda” and the adoption of children by foreign same-sex couples.
In a film called “The Second Baptism of Rus,” shown recently on Russian state television, Mr. Putin credited Prince Vladimir’s choice of religion with “building a centralized Russian state,” something he sees as a cornerstone of his leadership.
Mr. Putin recalled the story of his mother having him baptized in secret after his birth in 1952 because of Soviet repression of the church.
He described Communism as “just a simplified version of the religious principles shared by practically all the world’s traditional religions” and said that today’s turn to religion was “a spontaneous movement from the people themselves to turn back to their roots” in response to the ideological vacuum after the Soviet Union’s collapse in 1991.
Ukraine’s president, Viktor F. Yanukovich, appeared beside Mr. Putin during the service on Saturday, though relations between Moscow and Kiev have continued to be marred by battles over gas pipelines and other disputes despite a widely held view in Russia that Mr. Yanukovich would be more solidly aligned with Russia.
Ukraine is scheduled to sign an association agreement with the European Union in November.
While insisting that choices of international relations were Ukraine’s to make, Mr. Putin argued Saturday that Ukraine would fare better by deepening its political and economic ties with Russia.
On Saturday, Femen, the Ukrainian feminist group known for its bare-breasted protests, said three of its activists and a photojournalist were beaten and taken away by an “organized group of people” on the way to a protest of the celebrations.
On its Web site, Femen accused the spy agencies of Ukraine and Russia of being behind the attack, though it did not provide evidence.
The Kiev police said they had detained three women for “petty hooliganism” after they refused to cover up when they were spotted naked on the street.
The police Web site said a photographer who was accompanying them was detained for disobeying police orders.
It did not talk about beatings.
Femen later reported that its leader, Anna Hutsol, was beaten up while in a cafe on Saturday night and her laptop was taken.
Source: The New York Times