"I see nothing compromising in conversation between Trump and Ukraine President," Vladimir Putin said.

Russian President Vladimir Putin on Wednesday defended Donald Trump over accusations the US leader pressured Kiev to dig up dirt on a rival, saying there was "nothing compromising" in transcripts of the call.

"I see nothing compromising in the conversation between Trump and (Ukrainian leader Volodymyr) Zelensky," Putin said of the phone call that has sparked an impeachment probe in the US.

"President Trump turned to a colleague with a request to investigate possible corruption relating to members of the former administration," the Russian leader said at an energy forum in Moscow.

"Any head of state would have had to do the same."

"They have already been using any excuse to attack President Trump. Now it's Ukraine," Putin added.

Putin also took aim at the Mueller Report, which concluded that Russia tried to swing the 2016 election in the Republican's favour but did not establish evidence of collusion between the Trump camp and Moscow.

"He didn't find any evidence of us colluding with Trump in the past, but said there was a risk we might do so in the future... It would be funny if it weren't so sad," said Putin.

Asked if Russia would try to meddle in the US 2020 presidential election, Putin joked: "I'll let you into a secret -- yes! We absolutely will... Just don't tell anybody."

The White House last week released a transcript of a call this summer between Trump and a recently elected Zelensky.

It showed that Trump asked Zelensky to probe Democratic rival Joe Biden, and the Democrats are looking into whether Trump used a delayed $400 million (365.8 million euros) aid package as leverage.

Ukraine is fighting an ongoing war in its east against Russia-backed separatists, which broke out after Moscow's annexation of Crimea in 2014.