An electrical fire occurred in the engine room of the 2005-built ship, according to MANA News Agency.
The USCG said it launched an HC-144 Ocean Sentry aircrew who conducted an over flight of the vessel and confirmed that the fire had been extinguished by the crewmembers.
The 20 crewmembers aboard the ship, which is owned by the US shipping company Alliance Navigation LLC, are all accounted for with no reported injuries or medical conditions, the USCG said.
Following the incident, the 57,280 gross ton Alliance St. Louis has been on emergency back-up power.
“Coast Guard Sector New Orleans is maintaining a 2-hour communications schedule with the vessel and are broadcasting a notice to transiting vessels every 12 hours via VH-F channel 16,“ the USCG said.
The Alliance St. Louis has been awaiting a tug to arrive on scene to tow the vessel to Port Arthur, Texas.
The USCG is investigating the cause of the incident. No pollution has been reported.