Russian President Vladimir Putin said today an impromptu piano rendition he gave on the sidelines of a meeting in Beijing had been hampered by an out of tune instrument.

Putin was captured on camera on Sunday sitting down at a grand piano in a Chinese state residence, and performing a few slightly hesitant chords of two popular Soviet-era compositions, "Moscow Windows" and "Evening Song."

Asked at a news briefing in Beijing on Monday about his performance, Putin said he had just been idly toying around with the keys while he waited for his meeting to start with Chinese leader Xi Jinping on the sidelines of an international forum.

"It's a pity that the piano was out of tune," Putin said. "It was quite hard to play, even for me, someone who plays with two fingers. I cannot say I played, I was just pressing the keys with two or three fingers.

"I thought that if Mr Peskov is filming, it's probably for personal use, for the archive," Putin said, referring to his spokesman, Dmitry Peskov. "But they decided to post it. But never mind. I think I didn't let you down."

Another reporter at the news conference asked what tune Putin would play for US President Donald Trump if they were to meet.

"I don't know, I think we'd need to meet him, have a discussion, and depending on the result choose a melody," Putin replied.

Putin, a 64-year-old former KGB spy has demonstrated his skills on the piano in the past, although he has mostly cultivated a more macho image.

That has included riding a horse in Siberia, piloting a firefighting plane and diving in submersibles into the depths of Lake Baikal and the Black Sea off the Crimean coast.