Iran said on Saturday the US presence in Syria had been “wrong and illogical” from the start, in its first official reaction to President Donald Trump's decision to withdraw troops.

“The presence of American forces was from the very start, in principle, a wrong and illogical move and a primary cause of instability and insecurity in the region,” said foreign ministry spokesman Bahram Ghasemi on his Telegram channel.

Trump vowed on Thursday that the United States would no longer be the “policeman of the Middle East” as he ordered troops back from Syria.

Iran's Revolutionary Guards have a contingent of commanders and advisers deployed in Syria in support of President Bashar al-Assad, and have ferried weapons and thousands of militia fighters to the frontlines from various countries.

The United States currently has around 2,000 forces deployed in Syria in two areas along the Iraqi border that was partly aimed at keeping Iranian forces in check.