US Secretary of State Rex Tillerson arrives the meeting of Foreign Ministers of the G7 countries in Lucca, Italy, Monday, April 10, 2017.
In the wake of last week's chemcial attack, British Foreign Secretary Boris Johnson spearheaded a plan to impose targeted sanctions against Syrian and Russian military figures.
Meanwhile, Russia and Iran, President Assad's key military backers, are threatening retaliation if there are any further American air strikes and the task of breaking the present deadlocks over Syria remains enormous.
The Kremlin said on Monday that US Secretary of State Rex Tillerson will not meet President Vladimir Putin when he visits Moscow on Wednesday, a move that could point to tensions over a US missile attack on a Syrian air base last week.
Russian Federation condemned the U.S. missile strike as illegal and Putin said it would harm U.S. -Russia ties. Ministers meeting in the walled Tuscan city of Lucca strongly supported USA missile strikes that targeted a Syrian air base believed to have been used to launch the attack.
In a gesture weighted with symbolism, Tillerson visited the site of a World War II-era Nazi massacre in central Italy on Monday.
"We will rededicate ourselves to holding to account any and all who commit crimes against innocents anywhere in the world", he said, speaking at an Italian war memorial.
Although Russia has steadfastly supported Syrian President Bashar Assad's government, and they've coordinated military attacks together, Washington has never previously accused Moscow of complicity in any attack that involved the gassing of innocent civilians, including children. The US and its Western allies have placed the blame on the Syrian government, despite not presenting any evidence to prove Damascus was behind the deadly attack.
Tillerson and other officials have said the next priority is to create "zones of stability" in Syria where those displaced by civil war can live without fear of violence.
Syria, though, topped the agenda.
"Right now, I think everyone in the world sees Russian Federation as part of the problem", McMaster said. The next step would be to use United Nations talks to negotiate a political transition that could include Assad leaving power.
The U.S. has been conducting airstrikes in Syria since September 2014 and more recently has enabled a makeshift Syrian Arab and Kurdish force to isolate the city of Raqqa, which is the Islamic State's self-declared capital. What we are saying is, other countries have to ask themselves some hard questions.
Tillerson is the first USA cabinet member to visit Moscow since Trump took office after a campaign in which he called for closer ties with Russian Federation, including better cooperation to fight Islamist extremism in Syria. US President Donald Trump will attend North Atlantic Treaty Organisation and G7 leaders' summits in late May - in effect, the diplomatic can has been kicked down the road until then. Moscow also said it would keep military channels of communication open with Washington, but would not exchange any information through them.
A joint command centre comprising the forces of President Assad's allies, including Russian Federation and Iran, issued a statement saying the U.S. strike had crossed "red lines".
After the April 4 chemical attack, Trump said his attitude toward Assad "has changed very much" and Tillerson said "steps are underway" to organize a coalition to remove him from power. But Tillerson appeared more equivocal, saying on Sunday the USA priority in Syria was the defeat of ISIS.
It also is unclear if Trump, who has expressed skepticism of multilateral institutions such as the European Union and United Nations, will have patience for the protracted negotiations that a comprehensive deal on Syria would require. While Britain stressed pressure on Russian Federation and removing Assad, Germany's Gabriel emphasized that Russian Federation and Iran must be part of the peace process for Syria.
The vocal dispute between Russia and the United States over Syria complicates what has been a feature event; U.S. political drama for months has been about Russian meddling in USA elections and the blowback from Trump.