CNN - Russian Foreign Minister Sergey Lavrov began a meeting with his US counterpart Rex Tillerson in Moscow with a warning -- do not strike the Syrian regime again.
The two top diplomats are sitting down together in Moscow on Wednesday for what are expected to be painstaking talks after a chemical attack in northwestern Syria plunged the old Cold War enemies to a new low.
The two countries have traded barbs over last week's chemical attack, which killed 89 people, and prompted the US to carry out its first air strikes against the Syrian regime in the six-year conflict, taking out aircraft and infrastructure at a Syrian military air base.
The White House said Tuesday that Russia and Syria were trying to "confuse the world community about who is responsible" for the chemical attack.
The attack has been widely blamed on Syrian president Bashar al-Assad's regime, but Russia, Assad's most powerful ally, has denied the regime was responsible for the killings.
Lavrov said Wednesday that Russia "saw some very troubling actions regarding the attack on Syria."
"We believe it is fundamentally important not to let these actions happen again," Lavrov said, according to an official Russian interpreter.
He also complained about the mixed messages coming out of Washington on the Trump administration's policy on Syria, with the US envoy to the UN, Nikki Haley, making clear Assad should have no future in Syria as Tillerson took a softer line.
"I will be frank that we had a lot of questions regarding a lot of very ambiguous as well as contradictory ideas on a whole plethora of bilateral and international agenda coming from Washington," Lavrov said.
He also hit back at remarks Tillerson made a day earlier that Russia would have to decide whether it was with the US and the West in standing up against Assad, or against them.
Tillerson took a more diplomatic tone in his initial remarks, saying that he hoped to clarify "areas of common objectives, areas of common interests, even when our tactical approaches may be different."
"And to further clarify areas of sharp difference, so we can better understand why these differences exist and what the prospects for narrowing those differences may be."
US President Donald Trump ordered a Tomahawk missile strike against the Shayrat airfield in Syria, from where aircraft used in the chemical attack were launched.
The US claimed the strike destroyed 20% of Syria's operational aircraft, a figure disputed by Russia's Defense Ministry.