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Russian President Vladimir Putin's visit to Finland on Friday is expected to focus on cementing ties with its neighboring Western country amid heightened tensions in the region over sanctions and the Ukraine crisis.

Putin's trip to the small Nordic country — his first since the Ukraine crisis erupted in 2014 — comes as Russia has increased military activity in Eastern Europe, with reports of airspace violations. NATO responded with a reinforced presence in Estonia, Latvia and Lithuania, leading to growing debate in nonaligned Finland and Sweden on whether to join the western alliance.

"With this visit Moscow can demonstrate that despite attempts by the West and the EU to isolate it, there's a country that will welcome the Russian leader," said Markku Kangaspuro, director of research at the University of Helsinki. "And what's more, that country is in the tense Baltic Sea area."

Russia, which has complained about NATO encroaching on its sphere of influence, would take a dim view if Finland, with which it shares a 1,300-kilometer (800-mile) border, and Sweden were to join the alliance, says Andrei Kolesnikov, a senior associate at the Carnegie Moscow Center.

"The prospect of Finland and Sweden joining NATO has seemed more likely in recent months than at any time since the end of the Cold War," Kolesnikov said. "But in the long term, it's far from certain that such a move would benefit the two countries, given the inevitable backlash from Russia."

That concern of a "backlash" is strongly present in a recent security policy paper commissioned by the Finnish government and could be why polls in both Finland and Sweden have continued to show a majority against joining the alliance.

On Thursday, Putin warned that Russia would take retaliatory measures to counter NATO's military buildup near Russia's borders which he said was aimed at "undermining military parity that has formed over decades."

President Sauli Niinisto, who will host Putin at his summer residence in southwestern Finland, says Finland's security policy document is unlikely to be discussed. But, as the visit comes a week before a NATO security summit which will have security in the Baltic Sea region high on its agenda, regional security is bound to be on the agenda. Niinisto, although head of state of a non-NATO country, has been invited to attend the NATO talks.

"Niinisto doesn't want to rock the boat. He isn't a proponent of NATO membership and for the sake of stability he doesn't want to even raise such speculation," Kangaspuro said, adding that the two leaders probably will discuss border issues and furthering economic cooperation.

Russia used to be Finland's main trading partner, but trade last year dropped more than 30 percent.

Putin, hailing from St. Petersburg near the Finnish border, has visited Finland several times. He came to Niinisto's summer residence three years ago on a working visit, and the two leaders last met in Moscow in March, when Putin agreed to halt the flow of illegal migrants through Russia to northern Finnish border crossing points.

Putin's spokesman, Dmitry Peskov, on Wednesday described the working visit as "a regular exchange of opinions ... with one of our closest partners."

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Nataliya Vasilyeva in Moscow contributed to this report.