US forces established control over an Iraqi border post on the main road to Jordan on Friday after it was abandoned by Iraqi officials.
Reuters correspondent Edmund Blair reported from the Trebeel border post, 550 km (340 miles) west of Baghdad, that the offices were now guarded by a US Humvee all-terrain vehicle. An American soldier at the border post wished travellers a pleasant journey but declined to make any comment to reporters.
Asked when he had arrived, he said: "I cannot answer that."
The few Iraqi officials who had been at the border post appeared to have fled in a hurry following the collapse of Saddam Hussein's 24-year rule in Baghdad on Wednesday.
Blair found food left half-eaten on a grubby kitchen table when he arrived on Thursday evening. But no Iraqi officials.
Border files with lists of visitors were strewn near the old waiting room. A huge portrait of Saddam had been torn.
An electric fire had still been burning in one office and an air conditioner rumbled on in another despite the cool evening air. Three rocket-propelled grenades lay on a table next to a small Iraqi flag.