"In the long run, it would be more hard for the two countries to work together".
"Final decisions haven't been made", White House Press Secretary Sarah Sanders said.
US President Donald Trump posted a fiery tweet earlier on Wednesday, in which he warned Russian Federation - one of Syria's key supporters in the war against foreign-backed militancy - that it should get prepared to "shoot down" missiles that the US military would soon rain down over Syrian targets.
His tweet came one hour after he warned of a forthcoming response to suspected chemical weapons attack in Syria, declaring that "smart" missiles will be coming and blasting Moscow for standing by Syrian President Bashar al-Assad.
A Swedish draft resolution, circulated to council members Thursday and obtained by AP, would also express the council's determination to establish "a new impartial, independent and professional" investigative body to determine responsibility for the use of chemical weapons in Syria.
"We stand ready to provide military options if they are appropriate as the President determined", Mattis said.
But, didn't he just tweet about Russian Federation and Syria needing to get ready for some missiles headed their way?
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He says claims of a chemical attack were fabricated and "can't serve as a pretext for any forceful actions".
Maria Zakharova, spokeswoman for the Russian Foreign Ministry, wrote on Facebook: "Smart missiles should fly towards terrorists, and not towards the lawful government which has been fighting worldwide terrorism on its territory for several years".
"Russia vows to shoot down any and all missiles fired at Syria", he said.
Trump mocked Moscow's threat to shoot down any United States missiles targeting Syria and pilloried Moscow for its ties to the regime of Bashar al-Assad.
Donald Trump has tweeted that he wants the world to "Stop the arms race" minutes after threatening to launch missiles at Russian forces in Syria.
In a series of Twitter broadsides that coincided with Russia-focused segments on his favoured channel Fox News, Trump opened the door to military attacks against the Kremlin's Syrian allies and voiced the toughest anti-Russian rhetoric of his presidency.
The freakish missive was issued 40 minutes after Trump vowed to pelt Russian forces who are supporting Syrian President Bashar al-Assad.
Russian Federation is disputing the claim that Assad's government was behind the attack; Trump has said evidence indicates otherwise. Syria denies the accusation.