Officials are trying to determine why a drone being used as part of a Navy training exercise malfunctioned off the Ventura County coast Saturday.
Two sailors suffered minor burns in the incident, the Navy said in a statement.
A spokeswoman for the U.S. Third Fleet told the Associated Press that it is unclear what went wrong.
The ship sustained some damage and is returning to its home port of San Diego, the Navy said.
The sailors aboard the guided-missile cruiser Chancellorsville were using the drone to test the ship's radar-tracking system, something done on a regular basis. The drone, a 13-foot-long aircraft with a wingspan of nearly 6 feet, was being controlled from Point Mugu.
Around 1:25 p.m., the drone slammed into the port side of the ship, which has a crew of about 300.