The tanker carrying $100 million worth of disputed Kurdish crude oil is moving for the first time since July 27, AIS ship tracking data showed on Wednesday.
The status of the tanker, called United Kalavrvta, changed to "underway using engine" from "at anchor", but it was still 95 percent full, the data used by the U.S. Coast Guard and Reuters showed.
The ship was still in the Galveston Offshore Lightering Area, with Galveston still listed as its destination, according to satellite tracking.
The ship has been in limbo for weeks after its would-be buyer balked at taking delivery of the cargo. Baghdad has filed a lawsuit in a U.S. court saying exports by the Kurdistan Regional Government (KRG) are illegal, while the KRG argues they are allowed under the Iraqi constitution.
(Reporting by Josephine Mason; Editing by David Gregorio)