North Korea fired several projectiles off its eastern coast into the sea off Japan's northwest early on Monday in what appears to be the second launch in a month, reports Reuters citing South Korean and Japanese officials.
South Korean officials said the missiles flew about 1,000 kilometers, or 620 miles, into waters off its east coast.
Some of the missiles landed in waters as close as 300 km (190 miles) from Japan's northwest coast, Japan's Defence Minister Tomomi Inada said in Tokyo.
Japanese Prime Minister Shinzo Abe said "strong protests" had been lodged with nuclear-armed North Korea.
"The launches are clearly in violation of (United Nations) Security Council resolutions. It is an extremely dangerous action," Abe told parliament.
South Korea's acting President Hwang Kyo-ahn condemned the launches as a direct challenge to the international community and said Seoul would swiftly deploy a U.S. anti-missile defense system despite angry objections from China.