Missiles fired by North Korea were tests of a new "railway-borne missile system", according to the state news agency KCNA.
The missiles flew 497 miles (800km) before striking a target in the sea off North Korea’s east coast, the agency said.
On Wednesday, South Korean and Japanese authorities announced they had detected the launch of two ballistic missiles from North Korea.
It comes just days after it tested a cruise missile that analysts said could have nuclear capabilities.
Wednesday’s test was reportedly conducted by a railway-borne missile regiment that had been organised earlier this year.
"The railway-borne missile system serves as an efficient counter-strike means capable of dealing a harsh multi-concurrent blow to the threat-posing forces," said Pak Jong Chon, a North Korean marshal and a member of the Presidium of the Politburo of the ruling Workers’ Party of Korea, who oversaw the test, according to KCNA.
Tensions increased further after South Korea tested its own ballistic missiles later on Wednesday.
Kim Yo Jong, the powerful sister of North Korean leader Kim Jong Un, criticised South Korean President Moon Jae-in for comments he made while observing his country’s missile tests, which included its first of a submarine-launched ballistic missile.
Mr Moon had said South Korea’s growing missile capabilities will serve as a "sure deterrence" against North Korean provocations.
But in a statement issued by state media, Ms Kim berated Mr Moon for describing North Korean weapons demonstrations as a provocation.
She also warned of a "complete destruction" of bilateral relations if he continued with what she described as the slander of North Korea.
Meanwhile, the UN Security Council scheduled emergency consultations on the North Korean missile launches late on Wednesday afternoon at the request of France and Estonia.
UN spokesman Stephane Dujarric expressed concern at the missile launches, reiterating that "diplomatic engagement remains the only pathway to sustainable peace and complete, verifiable denuclearisation of the Korean peninsula".
Experts have said North Korea is building up its weapons systems to apply pressure on the United States in the hopes of winning relief from economic sanctions aimed at forcing the country to abandon its nuclear arsenal.
US-led talks on the issue have been stalled for more than two years.
© Sky News 2021