KYIV -- Commemorations are taking place in Ukraine to mark the 1,025th anniversary of the conversion to Christianity of Kievan Rus, the medieval Slavic state that laid the Orthodox foundations for modern-day Russia, Belarus, and Ukraine.
The day began with a prayer service at St. Vladimir Hill, named in honor of Kievan Rus leader Vladimir the Great, who ordered the baptism of his kingdom in 988.
The service, led by Russian Patriarch Kirill and attended by Russian President Vladimir Putin and his Ukrainian counterpart, Viktor Yanukovych, sought to emphasize Orthodox unity.
"We take joy in the fact that you are standing together," Kirill said. "It signifies your communal participation, and together with you, the communal participation of our peoples -- not only in celebrating the historical fact of this holiday, but in all that Christianization has brought to our land."
It was a message Putin was to repeat throughout the day as he sought to reassert Russia's influence in Ukraine at a time when Kyiv is looking to closer ties with the West.
WATCH: Russian Patriarch Leads Prayer
After a visit to Kyiv's historic Pechera Monastery, the two men headed into bilateral talks, in which Putin was expected to discourage Yanukovych from signing an Association Agreement with the European Union at a summit in Vilnius in November.
Addressing Yanukovych, Putin spoke of the countries' "common roots" and said, "We are ready, based on what our predecessors have achieved, to move forward."
In addition to the EU deal, Putin was hoping to persuade Ukraine to drop EU free-trade deals in favor of joining the Eurasian Customs Union grouping Kazakhstan, Belarus, and Russia.
Yanukovych, for his part, acknowledged "mutual interests" between the two neighbors. But during a speech on July 26 ahead of Putin's arrival, he appeared to suggest that Moscow was using a religious occasion to pursue its political goals.
"We will not allow the use of churches and religious organizations by some political powers to serve their own narrow interests," he said. "This also applies to foreign groups through which religious organizations sometimes aim to influence the political situation in Ukraine."
PHOTO GALLERY: Kievan Rus Commemorations
Russian President Vladimir Putin kisses an icon during a service and ceremony in Kyiv on July 27 to celebrate the 1,025th anniversary of Christianity in Ukraine, Belarus, and Russia.
Patriarch of Moscow and All Russia Kirill (center) participates in a public prayer in Kyiv on July 27.
Kyiv Metropolitan Filaret also took part in the ceremonies.
Ukrainian President Viktor Yanukovych takes part in the opening of an exhibition marking the 1,025th anniversary of the baptism of Kievan Rus on July 26.
The faithful kiss the cross of St. Andrew the Apostle, which is on loan from its home cathedral in Patras, Greece.
Russian Patriarch Kirill (left) and Ukrainian President Viktor Yanukovych greet each other before a public prayer in Kyiv on July 27.
Members of Ukraine's ultranationalist Svoboda party defied a ban on public demonstrations and gathered near the prayer site to stage an anti-Russia protest on July 27.
Russian President Vladimir Putin (left) and Ukrainian President Viktor Yanukovych cross themselves during a service and an official ceremony in Kyiv.
Russia President Vladimir Putin in Kyiv on July 27
Russian Patriarch Kirill (center) participates in the ceremonies at Volodymyrska Hill in Kyiv.
Russian Patriarch Kirill recites a prayer at Volodymyrska Hill in Kyiv.
Orthodox believers wait in line to kiss an icon during the service and a ceremony in Kyiv.
Ukrainian President Viktor Yanukovych crosses himself in front of an icon during a service and ceremony in Kyiv on July 27.
Many Ukrainians say they resent Moscow's attempt to steal the weekend limelight from Kyiv, the onetime capital of Kievan Rus and the site of Vladimir the Great's own baptism.
Top Orthodox clergy from around the world have traveled to Kyiv for the anniversary, which is also being attended by Moldovan President Nicolae Timofti and Serbian President Tomislav Nikolic.
Defying a court ban on public protests, close to 100 members of Ukraine's ultranationalist Svoboda party gathered near the St. Vladimir prayer site to vocalize their objections to what they see as Russian meddling.
Protesters chanted slogans and held posters showing pictures of Kirill and Putin and reading, "The capital of Kievan Rus welcomes its guests from the suburbs."
WATCH: Activists Protest Putin, Patriarch (In Ukrainian)
Speaking through a megaphone, Svoboda member Andriy Ilenko criticized the high security and what he described as arrogant behavior on the part of the Russian patriarch.
"There are unprecedented security measures, cordons, and police," he said. "And even the parishioners of the Moscow patriarchy cannot go and see [Patriarch Kirill] Gundayev. They won't let them in. They show contempt for them and treat them like rednecks."
The founder of the Ukrainian feminist movement Femen, meanwhile, was attacked early on July 27 in what the group is calling a case of political intimidation.
Anna Hutsol was punched in the face while entering her apartment building after walking her dog. Her unidentified assailant then fled with the dog.
The attack comes three days after one of the group's male activists, Viktor Svyatskiy, was brutally beaten
by unknown assailants, leaving him with a broken jaw and missing teeth.
Femen, whose bare-breasted protesters have already succeeded in confronting both Putin and Kirill, say the attacks are an attempt to silence its activists during the Russian visit.
Commemorations of the Kievan Rus anniversary are expected to continue on July 28 in Ukraine's port city of Sevastopol before moving on to Belarus.
With reporting by ITAR-TASS and AFP