SEOUL, Aug 29 (Reuters) - The top U.S. and South Korean military officers agreed to make a strong response to North Korea's latest ballistic missile launch on Tuesday, including possible unspecified military measures, South Korea's Yonhap news agency said.

The chairmen of both countries' Joint Chiefs of Staff agreed on a phone call "to take response measures at the earliest possible time that can demonstrate the alliance's strong will including military measures," Yonhap reported, quoting the South Korean military.

The Office of the Joint Chiefs of Staff in Seoul could not be reached immediately for confirmation. A South Korean defence ministry official said there was no immediate plan to change joint military drills being conducted by the South Korean and U.S. militaries. (Reporting by Jack Kim and Heekyong Yang; Editing by Paul Tait)