The Russian firm that developed the engine of the Naro space rocket’s first-stage booster says a malfunction in the rocket’s control system could have led to the Naro’s failed launch.

Russia’s Interfax news agency said NPO Energomash raised the possibility on Saturday. The Russian firm also said that it should not be blamed for the Naro’s failed launch, stressing that the engine it developed for Naro had operated as planned.

A senior official at the firm said a delegation the firm sent to South Korea had not mentioned anything significant on engine operations, adding that more verification processes are necessary.