North Korea showed off the missiles on transporter-erector-launchers during an April 15 parade to honor the birth of the country's late founder Kim Il-sung, Yonhap news agency reported Tuesday.
The German experts said the missiles are nothing to worry about, as they are just mock-ups.
"At first glance, the missile seems capable of covering a range of perhaps 10,000 kilometers [6,213 miles]. However, a closer look reveals that all of the presented missiles are mock-ups," Markus Schiller and Robert H. Schmucker, analysts with Schmucker Technology in Germany, wrote in a report posted on a nuclear arms control and non-proliferation blog last week.
The two said, "At a closer look, it is impossible to find a real warhead separation plane on any of the observed [intercontinental ballistic missiles]," adding that the missiles displayed in the parade indicate they are mock-ups.
"A real warhead's casing has to resist thermal and structural loads of an atmospheric re-entry and is certainly not designed this way," the experts said.
"There is no doubt that these missiles were mock-ups," the two wrote in the report.
"For now, the ICBM presentation was nothing else than a nice dog and pony show," the two said.