The rockets, which are believed to be old Soviet-developed FROG rockets that?DPRK has had since the 1960s, flew for 60 km (37 miles) before crashing into the sea, Yonhap said.
Six days ago, DPRK had fired 25 short-range rockets into the sea off its east coast.
ROK believes the short-range rocket launches conducted by DPRK this month are an "armed protest" against the ROK-U.S. military drills that are currently taking place. DPRK has denounced the joint military exercises as a preparation for war while Seoul and Washington have said the annual drills are defensive in nature.
Early last year, DPRK conducted its third nuclear weapons test, having successfully launched a long-range rocket in 2012 that critics say was aimed at proving technology for an intercontinental ballistic missile.
Both of those are banned under UN sanctions.