US President Donald Trump has spoken by phone with German Chancellor Angela Merkel and Italian Prime Minister Paolo Gentiloni, ahead of a summit of the Group of 20 leading economies.
The two-day G20 summit, which starts in Hamburg on Friday, comes just over a month after a G7 summit in Sicily showed deep divisions between Mr Trump and other Western leaders on climate change, trade and migration.
A fractious first NATO summit with Mr Trump also left European allies wondering where the military alliance goes next.
Mr Trump will hold separate meetings with various leaders in Hamburg, including Ms Merkel.
The Kremlin has said President Vladimir Putin and Mr Trump will meet on Friday on the sidelines of the summit.
In remarks last week, Ms Merkel raised the prospect of an open clash with Mr Trump at the Hamburg summit, although some Trump administration officials have played down the discord.
Since Mr Trump was elected US president, Russian has been keenly anticipating his first meeting with Mr Putin, hoping it would trigger a reset in US-Russia relations that plunged to post-Cold War lows under Mr Trump's predecessor Barack Obama.
But with Mr Trump embroiled in controversy at home over his associates' potential links to Moscow, the session with Mr Putin has become a minefield, with too warm a meeting would allow Mr Trump's domestic opponents to accuse him of being a Kremlin stooge.
During his presidential campaign, Mr Trump praised Russian President Putin as a "strong leader" with whom he would like to reset tense US-Russian relations.
