The search for a unified approach to the Syria conflict after last week’s suspected chemical attack looks set to dominate talks between the G7 group of leading nations in Italy on Monday.
Foreign ministers will focus on how to pressure Russia to distance itself from Syrian President Bashar al-Assad.
Allies will also be seeking clarity from the US on its Syria policy, after some apparently mixed messages.
US Secretary of State Rex Tillerson strongly criticised Russia on Sunday.
He said that it had failed to prevent Syria from carrying out a chemical attack on the rebel-held town of Khan Sheikhoun last Wednesday which left 89 people dead.
But he also clarified there had been “no change to our military posture” in Syria following a retaliatory US strike against a Syrian airbase, and that Washington’s “first priority” in Syria was to defeat so-called Islamic State (IS).