US President Donald Trump's order to withdraw US troops from Syria also signifies an end to the US air campaign against Islamic State there, US officials told Reuters yesterday, speaking on condition of anonymity.
Trump's surprise decision on Wednesday to completely withdraw U.S. troops from the country triggered criticism from some Republicans and concern from America's allies.
An end to the US air war will likely heighten fears that Islamic State, which has lost almost all of the territory it once controlled, could be given space to regroup.
The announcement of a withdrawal of troops on the ground had not necessarily meant an end to the air war since, unlike ground troops, major US air assets are not based in Syria and instead fly into the country from nearby nations. The US air operations center for the air war is located in Qatar.
The US-led air war has been critical to rolling back Islamic State and keeping pressure on the militant group in Iraq and Syria, with more than 100,000 bombs and missiles fired at targets in the two countries since 2015, according to Air Force data.
US officials told Reuters that the timing of the end of the air campaign would be linked to the withdrawal of the US forces but declined to set a date for when that would happen.
Some of Trump's fellow Republicans strongly criticised the move, saying they were not briefed ahead of time and that the move strengthened the hand of Russia and Iran, which both support Syrian President Bashar al Assad.
US officials, speaking on condition of anonymity, have told Reuters that US commanders on the ground are also concerned about the impact of a quick withdrawal and were surprised by the decision.
Trump's move also drew criticism from some US allies, including Britain and France, which said Islamic State militants had not been defeated and that its troops would remain in Syria.