A number of cruise missiles launched from a Russian ship and aimed at targets in Syria have crashed in Iran, two U.S. officials told CNN Thursday.

Monitoring by U.S. military and intelligence assets has concluded that at least four missiles crashed as they flew over Iran.

The U.S. believes, based on intelligence reports of damage assessments, that some buildings were damaged and civilians may have been hurt.

It's unclear where in Iran the missiles landed. The Russian ships have been positioned in the south Caspian Sea, meaning the likely flight path for missiles into Syria would cross over both Iran and Iraq.

The Russians have been firing a relatively new cruise missile called "Kaliber," using it for the first time in combat.

The Russian Defense Ministry, however, took strong issue with the CNN report in a posting on Facebook Thursday.

"Unlike CNN, we don't report quoting anonymous sources, but we show launches of our missiles and the targets they hit in real-time mode," the statement reads, noting that Russian drones are operating in Syria around the clock, presumably monitoring operations.

It continues, "No matter how unpleasant and unexpected it is for our colleagues in the Pentagon and Langley, our strike yesterday with precision-guided weapons at ISIS infrastructure in Syria hit its targets."

In response, one U.S. official familiar with the intelligence reports told CNN, "These are the people who told us there were no little green men in Crimea." (...)