Moscow (AFP) - Russian President Vladimir Putin on Wednesday met US Secretary of State Rex Tillerson after complaining of worsening ties with Donald Trump's administration as the two sides spar over Syria.
Putin received Tillerson at the Kremlin along with Russia's Foreign Minister Sergei Lavrov after the top diplomats held several hours of talks dominated by the fallout of an alleged chemical attack in Syria.
Despite initial hopes in Moscow of better ties with the US under Trump, the two powers have descended into a furious war of words over the incident and a retaliatory US missile strike against the forces of the Kremlin's ally Bashar al-Assad last week.
Russia has slammed Washington's attack on a Syrian airbase and, as Tillerson met Lavrov, Putin admitted that relations have worsened in the three months that Trump has been in office.
"You can say that the level of trust on a working level, especially on the military side, has not improved but most likely worsened," Putin said in the transcript of an interview with Mir television released by the Kremlin.
"Where is the proof that Syrian troops used chemical weapons? There isn't any. But there was a violation of international law. That is an obvious fact."
- 'Clarify differences' -
Tillerson, a former oil executive, might once have looked like the perfect envoy to mend strained ties, having worked closely with the Kremlin while negotiating deals for energy giant ExxonMobil.
But the underlying tensions between the former Cold War foes never went away and last week's chemical attack has left ties once again in crisis.
At the start of his meeting with Lavrov, Tillerson said he wanted to "clarify areas of common objectives, areas of common interest -- even where our tactical approaches may be different -- and further clarify areas of sharp difference."
During his visit -- the first to Moscow by a senior Trump administration official -- Tillerson was expected to challenge Russia to distance itself from Assad and his Iranian backers, an idea that the Kremlin dismissed as "absurd".
Lavrov told Tillerson Moscow was hoping to understand Washington's "real intentions" and warned that the Kremlin considered it "fundamentally important" to prevent more "unlawful" US strikes against its ally Syria.
In a further indication of the stark differences, Russia also slammed as "unacceptable" a proposed UN resolution put forward by the US, Britain and France on the alleged chemical attack, and said it would veto it in its current form at a vote expected later Wednesday.
The Western-backed resolution -- which was slightly revised from a proposal presented last week -- demands that the Syrian government cooperate with an investigation into the alleged attack.
"We are ready to throw our weight and resources behind diplomacy. We are ready to help bring this conflict to an end," US Ambassador Nikki Haley told the Security Council as it met.
Ahead of Tillerson's visit tempers rose sharply as US officials suggested Russian forces may have colluded in the latest atrocity blamed on Assad's regime that left 87 civilians dead including children in the town of Khan Sheikhun.
The White House compared Assad's tactics to those of World War II Nazi dictator Adolf Hitler, sparking widespread criticism for apparently ignoring the Holocaust.
Putin meanwhile accused Assad's opponents of planning to stage chemical attacks to be blamed on Damascus in order to lure the United States deeper into the conflict.
- Evacuations in Syria -
In a sign that the Kremlin is not set to drop its firm support for Assad, Syria's foreign minister is set to jet in to Moscow for talks with Lavrov on Thursday before a three-way meeting involving Iran's top diplomat on Friday.
As the powerbrokers wrangled over the six-year war in Syria that has cost some 320,000 lives, a deal on the ground to evacuate four besieged towns began Wednesday with an exchange of prisoners between rebels and government forces, local sources and state media said.
Thousands of people, both civilians and fighters, are expected to begin leaving government-held Fuaa and Kafraya and opposition-controlled Madaya and Zabadani later Wednesday.
The evacuations of the four besieged towns come under an agreement brokered by rebel backer Qatar and government ally Iran last month.