Street graffiti depicting Donald Trump passionately locking lips with Russian President Vladimir Putin went viral on social media in Lithuania Friday, appearing to show concern over the US White House hopeful's attitude toward Moscow.

The artwork in the capital Vilnius alludes to a famous 1979 photograph of then Soviet leader Leonid Brezhnev kissing communist East German president and ally Erich Honecker.

The "fraternal kiss" between the two Cold War-era communist leaders was immortalised in a famous piece of graffiti on the Berlin Wall.

"It seems we have a new Cold War, and America may have a president who seeks friendship with Russia," Dominykas Ceckauskas, who commissioned the giant mural on the outside wall of his burger restaurant, told AFP.

"We see many similarities between these two 'heroes' (Putin and Trump). They both have huge egos, and it's amusing to see they are getting along well," he said.

While relations between Washington and Moscow have been strained for years, Trump has defended Putin, calling him "a powerful leader". Putin in turn has hailed the "tremendous" Trump as "talented without any doubt."

For Lithuania and some eastern European nations once behind the Iron Curtain there are also growing concerns about the criticism of NATO by the presumptive Republican presidential nominee.

The alliance is regarded as a key security guarantee especially in the small Baltic states once under Moscow's thumb.

Lithuanian Foreign Minister Linas Linkevicius said last month that Trump's comment about an "obsolete NATO" reflects Russia's view of the Western defence alliance.

"Trump has notoriously stated that Putin is a strong leader, and that NATO is obsolete and expensive," Kestutis Girnius, associate professor of the Institute of International Relations and Political Science in Vilnius, told AFP.

"This graffiti in Vilnius expresses the fear of some Lithuanians that Donald Trump is likely to kowtow to Vladimir Putin and be indifferent to Lithuania's security concerns," he said.