North Korea announced its attempt to launch a new military reconnaissance satellite failed on Monday when a newly developed rocket engine exploded mid-flight, Reuters reported. 

This attempt followed a warning from Pyongyang about a satellite launch by June 4, aiming for its second spy satellite in orbit. Despite previous failures, North Korea successfully placed its first spy satellite in orbit in November.

“The launch of the new satellite carrier rocket failed when it exploded in mid-air during the flight of the first stage,” stated the deputy director general of North Korea’s National Aerospace Technology Administration via state media. According to a report by Reuters, initial analysis suggested the failure was due to a newly developed liquid fuel rocket motor, though other causes are being investigated.

South Korean and Japanese officials had earlier reported the apparent failure. The projectile was launched southward from North Korea’s west coast at 10:44 p.m. (1344 GMT), according to South Korea’s Joint Chiefs of Staff (JCS), Reuters reported. Large amounts of debris were detected in the sea just two minutes after launch.

Japanese Chief Cabinet Secretary Yoshimasa Hayashi said the object disappeared over the Yellow Sea, and the government believes nothing entered space. “

According to Reuters, Japanese public broadcaster NHK showed a video of what appeared to be an orange dot flying into the night sky and then bursting into flames. A Japanese defense ministry official suggested the flames indicated burning liquid fuel, with further analysis ongoing.

According to a report by Reuters, the launch appeared to originate from Dongchang-ri, where North Korea’s main space flight center is located. The Japanese government issued and then lifted an emergency warning for southern residents, stating the missile was not expected to fly over Japanese territory, Reuters reported.

According to a report by Reuters, Russian experts have visited North Korea to assist with its satellite and space rocket program. Pyongyang asserts it needs a military reconnaissance satellite to monitor U.S. and South Korean military activities.