South Korea’s presidential Blue House condemned in the strongest terms an attack against a cargo ship operated by a Korean shipper this month in the Strait of Hormuz and said it plans to respond once the source of the attack is identified, Reuters reports.

Experts conducted an initial forensic analysis of the damage to the port stern, a Blue House official said. The attack had led to a fire in the vessel’s engine room.

Namu, the vessel operated by the shipper HMM Co. , was not in violation of any rules in effect at the time in the waters off the United Arab Emirates and it was a case of an attack against a commercial vessel that cannot be justified, the official said.