TOKYO -- North Korea fired two ballistic missiles into the Sea of Japan on Wednesday, South Korea's military said, in the isolated nation's second test in less than a week.

The projectiles are not believed to have landed in Japan's exclusive economic zone, according to Japan's Cabinet Office.

The firings come days after Pyongyang said it carried out successful tests of a new long-range cruise missile over the weekend. Neither the U.S., Japan or South Korea have yet provided details of the missile that analysts see as possibly the country's first such weapon with a nuclear capability.

The launch of ballistic missiles "threatens the peace and security of our country and the region and is outrageous. We strongly protest and condemn it," Japanese Prime Minister Yoshihide Suga told reporters in Tokyo. He added that he instructed relevant ministries and agencies to collect and analyze information on the launches.

The launch was reported as Sung Kim, the U.S. special envoy for North Korea, is in Tokyo for talks with Japanese and South Korean counterparts. Chinese Foreign Minister Wang Yi is also in Seoul for dialogue with his opposite number there.

North Korea's official KCNA news service called the cruise missile a "a strategic weapon of great significance in meeting the key target of the five-year plan for the development of the defense science and the weapon system" set forth at the Workers' Party congress early this year.

South Korea recently conducted its first successful underwater test of a submarine-launched ballistic missile, it was revealed last week. This makes South Korea the eighth country to possess such capabilities, joining peers such as the U.S., China, Russia, the U.K., France and India. North Korea was the seventh.

The South Korean military was set to provide details of the test later Wednesday.