A private U.S. security think tank says no signs of nuclear facilities have been found in underground tunnels Myanmar is building allegedly with help from North Korea.

According to Voice of America, Paul Brannan, a senior research analyst at the Washington-based Institute for Science and International Security (ISIS), said the think tank’s satellite photos show no indications of nuclear facilities in the tunnels.

He said the photos reveal indoor or underground reservoirs, floodgates and tunnel entrances, but no nuclear facilities.

But the institute quoted an intelligence source as saying that North Korea exported unspecified precision machinery to Myanmar and that officials from Pyongyang-based Namchongang Trading Corporation are staying in the Southeastern country.

Namchongang has been slapped with financial sanctions by the U.N. Security Council for its alleged involvement in North Korea’s nuclear development.