The projectiles were launched from northeastern South Hamgyong province, South Korea's Joint Chiefs of Staff said.
North Korea has conducted nine rounds of launches since early May, and Saturday's missile test follows the firing of two projectiles on August 16.
Ri's blistering rhetoric and the missile launches may dim the prospect for an early resumption of nuclear negotiations between the U.S. and North Korea.
USA envoy on North Korea Stephen Biegun was in Seoul this week to discuss ways to get negotiations back on track.
"The projectiles flew roughly 380 kilometers, reached an altitude of 97 kilometers and hit a maximum speed of over Mach 6-point-5, which is about 8,000 kilometers an hour".
The Japanese government said the suspected missiles caused no damage and did not land in its territorial waters. Foreign Minister Ri Yong Ho also called U.S. Secretary of State Mike Pompeo a "poisonous plant of American diplomacy" and vowed to "shutter the absurd dream" that sanctions will force a change in Pyongyang.
Pyongyang fires a new weapon, part of its missile testing into its eastern coast.
North Korea's latest rhetoric over the US-South Korean military drills had focused on South Korea, not the United States.
Japanese Defence Minister Takeshi Iwaya said that North Korea's missile launches were a clear violation of United Nations resolutions and can not be ignored.
"Timing this when Japan-South Korea ties are at their worst in decades, and just after Seoul pulled out of GSOMIA with Japan, would be all-to-predictably be right in the playbook of the Kim regime", said J. Berkshire Miller, deputy director at the MacDonald Laurier Institute and a senior fellow at the Japan Institute of International Affairs.
South Korea officially informed Japan on Friday of its decision to scrap an intelligence-sharing agreement, which Japanese Minister of Defense Takeshi Iwaya said was regrettable and showed it failed to appreciate the growing security threat posed by North Korea.
Talks have been stalled since Trump's visit to the Demilitarized Zone between the two Koreas, where he met with Kim, in late June.
South Korea's presidential office said it'll hold an unscheduled meeting to discuss the North Korean launches.