In a statement issued Saturday night, the State Department gives no details about how many personnel had remained in Yemen and where they had been relocated.
Earlier Saturday, Yemeni security and military officials had said that US troops including Special Forces commandos were evacuating from an air base near the southern city of al-Houta.
The Al Anad air base, Yemen's largest, was believed to have had some 100 American troops stationed there.
A State Department spokesman, Jeff Rathke, says the US continues to monitor terrorist threats emanating from Yemen and will take action to disrupt imminent threats to the US and its citizens, AP reported.