Ain al-Asad air base is located in the western Anbar province.
On Saturday, defence systems at Ain al-Asad intercepted and shot down two drones while they were hovering near the base.
There has been a spike in attacks against US forces in Iraq and Syria since the conflict between Israel and Hamas fighters in Gaza broke out.
On Sunday, the Pentagon announced, in response to recent attacks on American troops in the region, the US will send a Terminal High Altitude Area Defense (THAAD) system and additional Patriot air defense missile system battalions to the Middle East.
The United States has sent a significant amount of naval power to the Middle East in recent weeks, including two aircraft carriers, their support ships and about 2,000 Marines.
Washington is on heightened alert for activity by armed groups as regional tensions soar during the Israel-Hamas war.