McMaster, Cornyn and Cardin spoke on "Fox News Sunday", Tillerson appeared on ABC's "This Week" and CBS' "", Haley and Graham were on NBC's "Meet the Press" and Haley also appeared on CNN's "State of the Union".
The April 4 chemical weapons attack on the rebel-held town in Idlib province left almost 90 people dead.
The U.S. cruise missile strike on Thursday, meant to dissuade Assad from using chemical weapons again, gives Tillerson more credibility with Russian officials and will boost his efforts, observers and former officials said.
"The prime minister and the president agreed that a window of opportunity now exists in which to persuade Russian Federation that its alliance with Assad is no longer in its strategic interest", the spokeswoman said. The officials did not make clear precisely when the U.S. came to this conclusion about the Assad regime's motives. "It is unclear whether Russian Federation failed to take this obligation seriously and whether Russian Federation has been incompetent".
Syrian President Bashar Assad's regime is aligned with that of Vladimir Putin. The Kremlin declined to say whether Putin would meet with Tillerson, in line with its usual practice of not announcing such meetings ahead of time.
Top diplomats from the seven major advanced economies were in Italy for their annual two-day meeting which had initially been expected to focus on talks with new US Secretary of State Rex Tillerson about hotspots like Libya, Iran and Ukraine.
Tillerson's visit is unfolding amid a sense of urgency.
Last week's nerve gas attack in the rebel-held town of Khan Sheikhoun, which killed more than 80 people, stirred President Donald Trump - who was previously cool to the idea of US intervention - to strike for the first time at Assad's forces. Residents in the town place the death toll at more than 80.
(L to R) E.U. High Representative for Foreign Affairs Federica Mogherini, German Foreign Minister Sigmar Gabriel, U.S. Secretary of State Rex Tillerson, Canada's Foreign Affairs Minister Chrystia Freeland, Italy's Foreign Minister Angelino Alfano, France's Foreign Minister Jean-Marc Ayrault, Britain's Foreign Secretary Boris Johnson and Japanese Minister of Foreign Affairs Fumio KishidaItaly pose for a family photo during a G7 for foreign ministers in Lucca, Italy April 10, 2017. Stick with that guy. "That is why we are here to work all together for peace and liberty".
The allegation of Russian foreknowledge is grave, even by the standards of the now dismal U.S.
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Sebastian Vettel battled past his teammate to take second place, whilst Red Bull were having their own inter-team battle. So it seemed a reasonable forecast that Vettel would be quicker and more wily and take a second win for Ferrari .
Kremlin spokesman Dmitry Peskov said that Moscow is not aware of any possible new USA sanctions against Russian Federation over Syria, as neither President Donald Trump or his administration have made any statements.
Separately, a senior U.S. official suggested that Russian forces must have had foreknowledge of the chemical attack, which left at least 87 dead in the northern Syrian town of Khan Sheikhun.
"We do not have any information that suggests that Russian Federation was part of the military attack undertaken using the chemical weapons", Tillerson said.
Stavridis's comments came days after the United States launched a missile strike on a Syrian military air base on April 6, The Hill magazine reported.
Four years ago, in August, 2013, the Syrian regime had mounted a chemical weapons attack outside Damascus, and then President Barack Obama prepared to strike at the al-Assad regime, but Obama decided instead to put the matter to a vote in Congress.
If Washington does nothing to improve relations, the foreign ministry warned Monday, "Moscow will react reciprocally". The inclusion of those countries is important because the USA strategy for Syria involves enlisting help from Mideast nations to ensure security and stability in Syria after the Islamic State group is defeated.
Before the April 7 missile strikes on Syria, US President Donald Trump had indicated he would be less interventionist than his predecessors and willing to overlook human rights abuses if it was in US interests.
But Russia would defend itself to ensure the safety of air bases and supply bases in Tartus, wherever a threat originated: by land, air or sea. Russian Federation has denounced the USA attack as an "aggression" and argued that the Syrian government wasn't responsible for the chemical attack.
The Trump administration has ramped up its rhetoric against both Assad and Putin in recent days. "Or Russia can maintain its alliance" with Syria and Iran.
Ahead of the summit, Russia's deputy foreign minister, Sergei Ryabkov, was reported to have accused the U.S. of "primitive, loutish rhetoric" on Syria as he said Mr Tillerson wanted to discuss no-fly zones in the war-torn country.
Seve was there for me, says Garcia
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