The Kremlin's spokesman says some contacts between Ukraine's leader and Russian President Vladimir Putin have taken place outside the public eye.

Dmitry Peskov, Putin's spokesman, did not specify how many contacts the Russian president has had with Ukrainian President Petro Poroshenko or when the most recent one took place.

Putin and Petroshenko met in Berlin in the fall of 2016 as part of a four-way summit aimed at resolving the conflict in eastern Ukraine, where a war with Russia-backed separatists has killed more than 10,000 people in the past three years.

Russian news agency reports, citing a national television broadcast that aired in the Far East on Sunday, quoted Peskov as saying: "Such meetings take place, but we don't report about them."