North Korea has test-fired two strategic long-range cruise missiles into the sea according to state media.
Leader Kim Jong Un oversaw the drill, staged over the Yellow Sea, and urged "unlimited and sustained" development of his country's nuclear weapons forces, the KCNA news agency reported.
It was apparently the first such test since early November.
The South Korean military said it detected the launch of multiple missiles from the Sunan area near Pyongyang, the Yonhap news agency said.
The goal of the exercise was to review the "counter-offensive response posture and combat capability of long-range missile sub-units," KCNA said.
Kim stated that the government and ruling party of North Korea "would as ever devote all their efforts to the unlimited and sustained development of the state nuclear combat force," the news agency added.
North Korea staged a ballistic missile test on 6 November, just over a week after US President Donald Trump, on a tour of the region, expressed interest in meeting with Kim.
Pyongyang did not respond to the offer.
At that time Mr Trump had just approved South Korea's plan to build a nuclear-powered submarine.
Analysts have said Seoul's plan to construct one of these atomic-driven vessels would likely draw an aggressive response from Pyongyang.
North Korea has significantly increased missile testing in recent years. Analysts say this drive is aimed at improving precision strike capabilities, challenging the United States as well as South Korea, and testing weapons before potentially exporting them to Russia.
Since Kim's 2019 summit with Trump collapsed over the scope of denuclearisation and sanctions relief, Pyongyang has repeatedly declared itself an "irreversible" nuclear state.
Mr Kim has since been emboldened by the war in Ukraine, securing critical support from Moscow after sending thousands of troops to fight alongside Russian forces.
