South Korean President Lee Jae Myung observed the first “successful” test launch of a domestically developed hypersonic glide vehicle (HGV) on Thursday, a capability experts say could keep Seoul’s missiles ahead of North Korean air defenses.

The Blue House said in a statement that the “successful test marked a significant step toward securing a new deterrent capable of striking key targets on the Korean Peninsula battlefield.” It came as the DPRK conducted two launches of reputed hypersonic missiles in recent weeks.

Thursday’s test was designed to verify the HGV’s core technologies under hypersonic flight conditions, including heat-resistant materials, guidance and