"That decision is still ahead of us, the secretary has not yet made that decision," McKenzie told reporters on Wednesday when asked about reports that the Pentagon plans to deploy around 3,900 more troops to the country.
McKenzie said no new US soldiers have started to flow into Afghanistan since Trump announced his decision to increase the US military's presence in the country.
"No decision has been made by the secretary. No deployment orders have been issued," he said.
Trump last week revealed his plan to increase US troop numbers in the country, in an about-face from his election campaign promises.
McKenzie on Wednesday revealed that the United States currently has approximately 11,000 troops stationed in Afghanistan.