The ICBM launch was followed by two short-range ballistic missiles on Tuesday and two strategic cruise missiles fired from a submarine last Sunday.
Recent aggression by Pyongyang has prompted Seoul and Tokyo to try to mend fences over historic disputes and boost security cooperation.
Just hours after the ICBM was fired Thursday, South Korean President Yoon Suk Yeol arrived in Japan for the first full-scale leaders’ summit between the countries in 12 years.
After their summit, Japanese Prime Minister Fumio Kishida said both countries wanted strong deterrence, and suspended security and ministerial talks would now resume. Yoon said the nations would also revive a military intelligence pact that Seoul put on hold as ties deteriorated.
Last year, North Korea declared itself an “irreversible” nuclear power, and leader Kim Jong Un recently called for an “exponential” increase in weapons production, including strategic nukes.
Earlier this month, Kim also ordered the North Korean military to intensify drills in preparation for a “real war”.