"We are going to stand with the 41 nations, largest wartime coalition in history, who are still committed to this effort", Mattis said at the Reagan National Defense Forum on Saturday.
On November 25, the Ukrainian Navy said Russian forces opened fire and seized three Ukrainian ships near the Kerch Strait, injuring six Ukrainian military sailors.
"There is no doubt the relationship has worsened", between the US and Russian Federation.
Mattis said that American intelligence is seeing "a continued effort" by Russian Federation to interfere in American elections, after they meddled in the 2016 presidential election.
UEFA launches third European club competition from 2021
VAR will also be used next year at the Nations Leagues finals and in the finals of the European Under-21 Championship. The competition will mirror the structure the format of the Champions League and Europa League tournaments.
"What we are seeing Putin do with his ripping up of global agreements. we're dealing with someone that we simply can not trust", the Pentagon chief added.
But independent researchers and social media firms countered this conclusion, saying that Russian Federation has indeed continued its online influence campaigns to sow distrust in American democratic institutions. He is not recognizing that what he is doing is actually creating an animosity against his people, "said Mattis".
In regards to the importance of the USA military presence in Afgahnistan, Secretary Mattis has said "If we leave, with 20-odd of the most unsafe terrorist groups in the world centered in that region, we know what will happen".
CNN chief White House correspondent Jim Acosta said "this is probably the revelation of the day".
U.S. Secretary of State Mike Pompeo on Saturday said the Ukraine events were the only reason Trump canceled his planned formal meeting with Putin in Argentina, not developments in Special Counsel Robert Mueller's Russian Federation probe.