“From the start, the entry and presence of American forces in the region has been a mistake, illogical and a source of tension, and a main cause of instability,” Iranian Foreign Ministry spokesman Bahram Qassemi said.
In a reversal from previously stated US policy, Trump on Wednesday ordered a “full” and “rapid” withdrawal of American troops from Syria as he vowed the United States would no longer be the "policeman of the Middle East."
Trump said in a tweet on Thursday that “Russia, Iran, Syria & many others are not happy” about the planned US withdrawal.
On Friday, Trump was reported to have ordered the start of withdrawing some 7,000 troops from Afghanistan, about half of the total number of American boots on the ground in the war-torn country.
The United States currently has around 2,000 forces deployed in Syria in two areas along the Turkish and Iraqi borders.
In Afghanistan, the US currently has a contingent of roughly 14,000 troops, besides 16,000 NATO and allied forces.
Afghanistan came under the US invasion in 2011 with the purported aim of toppling the Taliban but the terrorist group is now engaged in peace talks with the Americans.
“A detailed study of the history of the region's developments over the past decades also shows that the presence of an external element under various excuses in this sensitive and important area has had no result except tension, insecurity, and escalation of differences,” Qassemi said.
US troops have been deployed to Syria without the country’s consent and a UN mandate.
Iran, a key supporter of President Bashar al-Assad in Syria’s war, has sent military “advisers” to help fight terror groups.
Tehran has opposed the presence of foreign forces in Syria, except those — from Iran and Russia — which have been invited by the Assad government.
Reuters, AP and Press TV contributed to this story.