The North's media said the missiles were the same ones displayed during a military parade marking the birthday of late North Korean founder Kim Il-sung on April 15th.
The North's official Korean Central News Agency said that Thursday's launches were of "a powerful attack means capable of striking any enemy group of battleships attempting at military attack on the DPRK from the ground at will".
The missiles, which the South said flew about 125 miles, were tested in waters between the Korean peninsula and Japan, where U.S. aircraft carriers USS Carl Vinson and USS Ronald Reagan participated in joint exercises with the South Korean navy that ended earlier this week.
The North's missile tests present a hard challenge to new South Korean President Moon Jae-in, a liberal elected last month who has expressed a desire to reach out to Pyongyang.
In size and shape, the device looked like a North Korean drone found in 2014 on an island near the border, South Korea's Office of Joint Chiefs of Staff said in a statement, adding that authorities plan to conduct a close analysis.
South Korea's military says the missiles flew some 200 kilometres.
The future of the program has been uncertain since South Korea announced the suspension.
South Korean President Moon Jae-in said Thursday that North Korea "should immediately halt its nuclear and missile provocations", following a test launch of suspected anti-ship missiles earlier in the day.
The Security Council voted unanimously on June 2 to add 15 individuals and four entities linked to North Korea's nuclear and missile programmes to a United Nations sanctions blacklist.
Cruise missiles typically fly in a straight line while a ballistic missile flies miles into the air in an arc to reach its target, he said.
"It is incumbent on us to assume that North Korea today can range the United States with an ICBM carrying a nuclear warhead", Vice-Admiral James Syring, director of the MDA, told the House Armed Services Committee. The improved range indicates the North is pursuing weapons capable of reaching US aircraft carriers that operate from deeper positions, he said.
The North's claims can not be independently confirmed.
"Our government, as I have already clarified multiple times, will not back off at all or compromise regarding national security and people's safety", Moon said.
After the reported missile test, China reiterated its call on all parties involved in the situation to exercise restraint and make an effort to stabilize the situation in the region.
North Korea's military just completed testing on what it claims is a precision-guided munition (PGM).