President Vladimir Putin stressed the common history shared by Russia and Ukraine on Saturday as he attended politically charged religious festivities, highlighting a tug-of-war over Kiev's moves to integrate with the EU.
Arriving in Ukraine on a two-day visit to celebrate the 1025th anniversary of the arrival of Christianity in what was once known as Kievan Rus -- a vast territory comprising modern-day Ukraine and Russia -- Putin said the two majority Orthodox neighbours had to solve a "lot of joint issues."
"This is truly our common great holiday which reminds us of our spiritual unity, speaks of our common roots, reminds us that we together have done a lot over past centuries," Putin told Ukraine President Viktor Yanukovych during talks.
"Today the situation is different but we are full of determination to work together, relying on everything that was done by our forefathers, our predecessors. We are facing major, complex tasks."
Yanukovych for his part said the two countries had "lots of mutual interests."
The religious festivities, also attended by Serbian leader Tomislav Nikolic and Moldovan President Nicolae Timofti, come ahead of a November summit in Vilnius that could see the European Union sign a long-delayed association agreement with Ukraine.
Analysts say the Ukrainian talks may be a last-ditch effort by Putin to persuade Yanukovych to drop plans of closer ties with the European bloc and could shape the future of bilateral relations.
"Obviously, Putin will put pressure on Yanukovych, will try to dissuade him from signing the association agreement with the EU," Kiev-based analyst Oleksiy Haran said ahead of the visit.
Putin's spokesman Dmitry Peskov told AFP on the eve of the visit that closer bilateral ties between Kiev and Moscow would be discussed although no agreements would be signed.
The association agreement with Brussels has been repeatedly postponed after a Ukrainian court jailed former prime minister Yulia Tymoshenko for seven years in 2011, triggering a dramatic deterioration in ties and making Kiev more vulnerable to the Kremlin's advances.
In a sign of continuing tensions, the European Union said Friday Ukraine had to sort out a number of trade disputes if it wanted to sign the agreement.
"There are increasing concerns that the time is running out to find mutually acceptable solutions," the EU delegation to Ukraine said.
Since coming to power in 2010, Yanukovych has performed a delicate balancing act by seeking closer European ties while also trying to remain on good terms with prickly Soviet-era master Moscow.
Russia has sought to keep Ukraine in its orbit by exploiting Kiev's differences with the West and inviting its ex-Soviet neighbour to join the Moscow-led customs union.
Kiev has steadfastly resisted pressure from Moscow, which wants to gain control of Ukraine's gas pipeline network in exchange for cheaper gas.
Earlier Saturday, Putin, accompanied by Russian Orthodox Patriarch Kirill and Yanukovych, took part in a prayer service in Kiev amid a heavy police presence.
Overlooking the Dnipro River, the park where the ceremonial prayer took place hosts a monument to Prince Vladimir the Great, revered for converting ancient Rus to Christianity in 988.
The two leaders also met Ukraine's top Orthodox clerics and visited the country's main cathedral.
Ukraine-based feminist movement Femen, which branded the festivities "the holy gathering of post-Soviet dictators," said its leader Anna Hutsol was attacked Saturday morning, blaming Ukrainian special services.
The group said the assault was an act of intimidation but vowed to protest Putin's visit anyway. A male Femen activist was also brutally beaten on Wednesday.
Around 100 Ukrainian nationalists staged a rally to protest Putin's visit.
In a separate protest, activists protested against police impunity in Ukraine. Ten activists were detained.