The ship was on its way from Charleston to Antwerp with 2,876 containers at the time of the explosion, reported Containerisation International.
The tugs, the Fairmount Expedition and the Anglian Sovereign, are expected be on the scene by late Thursday or early Friday.
There is speculation that the cargo causing the explosion was the highly combustible bleaching agent calcium hypochlorite, but this has been denied by the Geneva-based Mediterranean Shipping Company (MSC), which said: "Please note that MSC does not carry this commodity and it was not on board MSC Flaminia."