UNITED NATIONS, Dec. 21 (Xinhua) -- U.S. President Donald Trump's decision to withdraw troops from Syria is premature, Swedish ambassador to the United Nations Olof Skoog said Friday.

"I think it's too early to disengage," Skoog told reporters at UN Headquarters in New York before walking into a Security Council meeting.

"We strongly believe that international engagement cannot end now -- actually it should be stepped up to ensure that we have all the forces that are coming in to support," he said.

"I believe everyone needs to stay engaged to ensure that there is a political process now, which is inclusive, and which leads to elections and a reformed constitution so that all Syrians feel that the country that is coming out of this terrible war is one where their rights are protected," he said.

Skoog warned Damascus against its complacency over its military victory on the battlefield.

"Parties may think that they have won the war. But it's a completely different thing about winning the peace. This is a message to the Syrian government," he said.

Skoog refused to comment on U.S. Defense Secretary Jim Mattis' resignation.

"No comments on that," he said with a smile.

Mattis' resignation came one day after Trump ordered the withdrawal of the 2,000 or so U.S. troops from Syria. Differences with Trump over Syria are believed to be one factor for Mattis' departure.