Two US defense officials told CNN on Thursday that the US military now assesses that Russian contractors believed to be funded by the Russian government participated in Wednesday's assault.
One official said that assessment is based on information obtained from monitoring communications in the area and from drone surveillance.
The second official said given the believed relationship between the contractors and the Russian government, it is difficult to imagine that Russian military forces in Syria were not aware of the contractors' activities and involvement in the attack. That official also said the military assesses that some of the Russian contractors were killed in the US counterstrike.
