Story highlights Trump tweeted Sunday that Tillerson was "wasting his time trying to negotiate" with North Korea

"President Trump's guidance to both Secretary Tillerson and me has been very clear that we would pursue the diplomatic effort," Mattis said Tuesday

Washington (CNN) Defense Secretary Jim Mattis told Congress Tuesday that President Donald Trump still backs diplomatic efforts to curb North Korea's nuclear and missile activity.

"President Trump's guidance to both Secretary Tillerson and me has been very clear that we would pursue the diplomatic effort," Mattis told the Senate Armed Services Committee during a hearing on the administration's new strategy for Afghanistan and South Asia.

He said that Trump's decision to dispatch Secretary of State Rex Tillerson to China was indicative of the President's "intent to work with other nations diplomatically."

Asked by Michigan Democratic Sen. Gary Peters whether Trump's Sunday tweets saying that Tillerson was "wasting his time trying to negotiate" with North Korea "pulled the rug out" from his chief diplomat, Mattis said that while Trump did not back direct talks with Pyongyang he did support diplomatic engagement with China and others to help tackle the issue of North Korea's weapons program.

"I believe that Secretary Tillerson's remarks about probing North Korea to see if they are ready to talk was what the President was referring to, not the diplomatic effort writ large," Mattis explained, referencing Tillerson's recent revelation that the US government maintained indirect channels of communication with the regime in North Korea.

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