Poland will not allow members of a Russian motorcycle club linked to President Vladimir Putin to cross its border and enter the European Union's territory, the Polish Foreign Ministry said on Friday, in a decision Moscow said was politically motivated.

The spat is likely to put further strain on bilateral relations, hampered for decades following World War II and damaged by Russia's recent role in the Ukraine crisis.

Some 50 members of the Night Wolves, a group blacklisted by the United States for taking part in Russia's annexation of Crimea, are taking part in a bike ride from Moscow to Berlin, commemorating the 70th anniversary of the end of World War Two.

"The Foreign Ministry has passed a diplomatic note to the Russian Embassy in Warsaw ... concerning a denial of entry to Poland to an organized group of motorcyclists, which included representatives of the Night Wolves club," the ministry said in a statement.

Ministry spokesman Marcin Wojciechowski told a news conference that Russia formally asked Poland last Monday to approve the motorcyclists' tour, due to start on Saturday.

"I want to reassure you that the decision was not a political one, but based on formal considerations," he said, adding that Russia was late with its request and did not provide details on the planned route, accommodation or list of participants.

The Russian Foreign Ministry said in a statement that Warsaw's allegations were a "blatant lie" and that all the necessary information was provided on time.

"It is obvious that the decision was politically motivated," the ministry said in its statement. "We express our strong protest over the decision of the Polish authorities."

Anna Komarova, spokeswoman for the Night Wolves in Moscow, said that the group is not going to change its plans and will leave Moscow on Saturday.

"We are not cancelling anything," Komarova told Reuters. "Poland is Poland: today this way, tomorrow another."

She said that the group has also not changed its plans to stop on the way in Katyn forest in Western Russia — site of the murder of 22,000 Polish officers by Joseph Stalin's NKVD secret policy in 1940. The site also contains the graves of many Russians executed on Stalin's orders.

The Polish Foreign Ministry allowed three other Russian motorcyclists' groups to enter Poland, Wojciechowski said.

He added that the Foreign Ministry is not in charge of regulating cross-border movement, but that to his knowledge the Night Wolves had not applied for visas needed to enter Poland.

"In taking the decision, we consulted our German and Czech partners," he added.

The Night Wolves have strongly backed the pro-Russian separatists in Ukraine and the support for them shown by Putin, who rode with them in a 2011 motorcycle parade.

Earlier this month, the Polish prime minister said the ride was a provocation, adding that the final decision on the matter would be made by border control officials.

"If it was to disturb our security, put the Polish people in danger of distress, law is there to be used," she told private radio To FM.

The Russian embassy in Warsaw was not immediately available for comment.