“On March 31, 12 Iranians of the Shahid Hemmat Industrial Group (SHIG) arrived in North Korea,” Yonhap quotes their source as saying. “The Iranians undoubtedly were there to observe the missile launch and receive test data from North Korea.”

The launch, which was widely seen as a breech of security agreements that prohibited North Korea from testing ballistic missiles, ended in failure when the rocket disintegrated shortly after take-off. North Korea claims that they were trying to put a satellite into space.

SHIG, the developer of Iran’s medium-range Shahab-3 ballistic missile, is the target of international sanctions.