"Troop numbers will fluctuate during this process," Robertson said on Thursday. "Out of concern for operational security, we will not discuss specific troop movements or timelines."
"The withdrawal is based on operational conditions on the ground, including conversations with our allies and partners, and is not be subject to an arbitrary timeline," Robertson said. He added that the US-led coalition is implementing "the orderly withdrawal of US forces."
In December, US President Donald Trump declared victory over the Daesh* terrorist group and said he would withdraw some 2,000 US troops currently deployed in the Middle Eastern country. Washington, however, said that it would not disclose a timeline for withdrawing its troops, and pledged that the US-led international coalition's fight against terrorism would continue.