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.
In his comments December 1, Jim Mattis also asserted that Moscow had tried to interfere in last month's midterm congressional elections.
Mattis also touched on the US intention to quit the Intermediate-Range Nuclear Forces Treaty, which the USA says Russian Federation is violating, according to a transcript provided in advance.
The U.S. intelligence community is reviewing data from the midterm elections for any evidence of foreign interference - with a report on the probe due to the administration later this month.
During the forum, former Defense Secretary Leon Panetta said Russian Federation will continue to undermine its neighbors, but also the United States in order to project its strength.
Defense Secretary Jim Mattis on Saturday took aim at Russian President Vladimir Putin, accusing him of trying to "muck around" in the USA midterm elections, of duplicity in arms control and of acting irresponsibly in last weekend's naval confrontation with Ukraine. Russian Federation seized Ukrainian ships.
Russia "brazenly violated" a 2003 agreement allowing Ukrainian ships free passage in the the strategic Kerch Strait when Russian forces fired on Ukrainian warships injuring servicemen and capturing three vessels with their crews Sunday, Mattis said in remarks prepared for the Reagan National Defense Forum.
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 risky terrorist groups in the world centered in that region, we know what will happen".
"Mr. Putin is clearly a slow learner".
"He is not recognising that what he is doing is actually creating the animosity against his people".
Speaking in Buenos Aires, Putin told reporters Saturday there were no preconditions for future bilateral talks with Trump. Trump abruptly canceled a planned meeting with Putin at the summit just two days before they were scheduled to sit down.