North Korea tested new tactical ballistic missiles using super-large warheads and modified cruise missiles on Wednesday as leader Kim Jong Un called for stronger conventional weapons and nuclear capabilities, state news agency KCNA reported.

The tests to improve weapons capabilities are required because of the grave threat posed by outside forces to the security of the country, Kim, who led the tests, was quoted as saying.

The account followed the firing of multiple short-range ballistic missiles on Wednesday reported by the South Korean military, which was the second time the North test-launched missiles in a week.

Last week, North Korea also unveiled a uranium enrichment facility, in its first such public report.

Kim stressed “the need to continue to bolster up the nuclear force and have the strongest military technical capability and overwhelming offensive capability in the field of conventional weapons too,” KCNA said.

Wednesday’s tests involved the new tactical ballistic Hwasongpho-11-Da-4.5 missiles, KCNA said, indicating it was part of a series of short-range ballistic missiles it had been developing.

The missile was mounted with a 4.5-ton super-large conventional warhead, KCNA said.

North Korea’s state media reported the tests of missiles with the same name in July, which was considered a partial success. On Thursday, state media released photographs of a projectile striking a target in a hilly area.

South Korea’s military said on Thursday two ballistic missiles landed in a mountainous area in the North’s northeast.

Such a missile launch test with an intention to hit an inland target is likely unprecedented, said Shin Seung-ki who is the head of research on North Korea’s military at the state-run Korea Institute for Defense Analyses in Seoul.

North Korea routinely test-launches missiles to drop in the sea or on an uninhabited island.

The particular missile with the Hwasongpho-11-Da-4.5 designation is still under development but Russia may want it soon if its performance and reliability can be guaranteed through further testing, Shin said.

“North Korea will want to shorten that time as much as possible,” he said.

Kyiv officials and independent experts have said there were signs some of the missiles used by Russia in the war against Ukraine were North Korean-made, including some that were produced this year. Moscow and Pyongyang both deny any illicit arms trade or shipments.

The North’s military also tested a strategic cruise missile that has been upgraded for combat use, KCNA said.

North Korea has criticized military drills by the South Korean and U.S. militaries, including a large-scale exercise conducted this summer, as preparations for war on the Korean peninsula.

The allies say the drills are defensive in nature and aimed at maintaining readiness against any North Korean aggression.