North Korea has confirmed it launched a "newly developed new-type tactical guided projectile", state news agency KCNA reports.
The report suggested North Korean leader Kim Jong-un did not inspect the launch on Thursday.
President Joe Biden on Thursday said the United States remained open to diplomacy with North Korea despite its missile tests this week, but warned there would be responses if North Korea escalates matters.
The new weapon is based on existing technology that was improved to carry a 2.5-ton warhead, KCNA reported.
The pair of weapons test-fired accurately hit a target 600km away, KCNA said.
"The development of this weapon system is of great significance in bolstering up the military power of the country and deterring all sorts of military threats," Ri Pyong Chol, the senior leader who oversaw the test, said, according to KCNA.
Photos released by state media showed a black-and-white painted missile blasting off from a military launch vehicle.