The White House said Wednesday it was too soon to say what Russian warplanes were targeting in Syria, or what may have actually been hit, when Moscow carried out its first strikes in the war-torn country.

Spokesman Josh Earnest said it was "too early for me to say what target they were aiming at and what targets were hit."

Earlier, a US defense official said the strikes had targeted opposition forces, and not Islamic State jihadists, as Moscow has said.