The response comes just after the Turks took down a Russian fighter plane along the Turkish-Syrian border after the Russian plane was repeatedly warned it was encroaching on Turkish airspace.
The Pentagon confirmed Tuesday that the Turkish authorities sent 10 warnings to the Russian plane before it shot it down.
The whereabouts and conditions of two pilots who were seen parachuting out of the plane are still unknown.
"We don't know the status of the two downed Russian pilots. Obviously we have observed local media, social media etc," Warren said. "We just don't know."
The Pentagon also said it was still working on confirming where the Russian warplane was flying before it was struck down.
"These things are not as clean as they are in the movies where you can kind of see where everything is," Warren said. "This is data that has to be collected and sorted through."
The Pentagon said that while the pieces were still coming together, it appears the most recent incident speaks to a larger narrative that the Russians' involvement in Syria is more directed at propping up and protecting the Assad regime than taking out ISIL.
"We are concerned when the Russians don't do what they say they are going to do," Warren said referring to the number of strikes the Russians have conducted that have benefited the Assad regime.
"We have seen the Russians already striking the forces that are moderate Syrian operation forces," Warren says. "Again, it flies directly in the face of what they would say they would do. They said they were here to strike ISIL."