Russia should abandon its support for Syrian President Bashar al-Assad after his repeated use of chemical weapons and join the US to map out a peaceful future for Syria, US Secretary of State Rex Tillerson says.
Tillerson's comments on Tuesday came an hour before he flew to Moscow from a Group of Seven meeting in Italy to meet his Russian counterpart.
The G7 foreign ministers urged Russia to pressure the Syrian government to end the six-year civil war but rejected a British call to impose new sanctions on Moscow over its support for Assad.
They said Russia could play a constructive role in ending the brutal conflict that has destabilised the Middle East.
"Russia can be a part of that future and play an important role," Tillerson said.
Or, he said, it could maintain its alliance with Syria, Iran and militant group Hezbollah, "which we believe is not going to serve Russia's interests longer-term".
Tillerson flew to Moscow carrying the G7's strong desire for a new start in Syria but few concrete proposals to make it happen.
The G-7 blames Assad's military for a deadly chemical attack that killed 87 people last week.
Ministers meeting in the Tuscan city of Lucca strongly supported US missile strikes that targeted a Syrian air base believed to have been used to launch the attack.
But they were divided about how to deal with Syria and Moscow.
Italian Foreign Minister Angelino Alfano, who hosted the G7 gathering, said "there is no consensus for further new sanctions".
"We must have a dialogue with Russia," he said.
"We must not push Russia into a corner."
Instead of sanctions, the meeting's final communique called for an investigation by the Organisation for the Prohibition of Chemical Weapons to determine who was responsible for the "war crime".
The US and Britain say there is little doubt Assad's forces are culpable.
The group's stance was a rebuff to British Foreign Secretary Boris Johnson, who said on Monday the G7 was considering new sanctions on Russian military figures to press Moscow to end military support for the "toxic" Assad government.
Tillerson's trip comes after an American official said the US had drawn a preliminary conclusion that Russia knew in advance of the chemical attack - an allegation that heightens already acute tensions between Washington and Moscow.