MOSCOW, June 17 (Reuters) - Four Ukrainian drones attacked the major Russian Novolipetsk Metallurgical Plant in the Lipetsk region during an overnight incident on Monday, its owner Novolipetsk Steel (NLMK) said.

NLMK said that the factory, which it says produces exclusively civilian products, continues to operate normally. The plant has already been attacked four times this year, NLMK said. (Reporting by Reuters; Writing by Maxim Rodionov; Editing by Jan Harvey)