MOSCOW, Dec. 27 (Xinhua) -- U.S. President Donald Trump is trying to "sit on two chairs at the same time" by keeping the military base in Iraq as a bridgehead for actions in Syria after withdrawing troops from Syria, a Russian lawmaker said Thursday.

"On the one hand, he still wants to demonstrate his intention to abandon the role of the global policeman, which implies shedding the blood of Americans for countries most people have never heard of," Konstantin Kosachev, chairman of the Foreign Affairs Committee of Russia's Federation Council, said on Facebook.

"On the other hand, Trump certainly aims to extinguish the discontent of the Republicans with the decision to withdraw the U.S. troops from Syria," he said.

The withdrawal of U.S. troops from Syria has already forced the resignation of Pentagon chief James Mattis, who clearly was more popular in Washington than Trump himself, Kosachev added.

Kosachev said he believes it is necessary to remind the United States at all levels that military actions in a neighboring country without the consent of its leadership and the mandate of the United Nations Security Council will mean a coercive intervention in the internal affairs of a sovereign state.

In a surprise visit to an Iraqi military base to celebrate Christmas, Trump denied any plans to withdraw U.S. troops from Iraq, shortly after he decided to pull U.S. servicemen out of neighboring Syria.