"They shook hands and said they will meet separately and see each other soon," said Kremlin spokesman Dmitry Peskov.

The billionaire tycoon and the ex-KGB agent's meeting later Thursday in the German port city of Hamburg promises to be one of the year's most scrutinised political encounters.

Ahead of the meeting, both men said they were looking forward to finally sitting down for talks.

"I look forward to all meetings today with world leaders, including my meeting with Vladimir Putin. Much to discuss," Trump wrote on Twitter.

Asked if Putin felt the same about the talks, Peskov said: "Affirmative".