North Korea fired a ballistic missile toward the East Sea on Wednesday, South Korea's military said, marking the second such launch in less than a week in an apparent protest against an upcoming combined military exercise between the South and the United States.

The Joint Chiefs of Staff (JCS) said it detected the missile launched from the Wonsan area on the east coast at around 6 a.m.

The missile flew more than 700 kilometers, with a detailed analysis on its specifications under way by South Korean and U.S. authorities, according to the JCS.

While the military has yet to specify the type or range of the missile, the range it provided suggests the launch likely involved a short-range missile, which typically flies 300 to 1,000 km.

North Korea has KN-23 short-range ballistic missiles, known as the North Korean version of Russia's Iskander, which have a maximum range of 700 to 800 kilometers.

The latest launch came six days after the North fired what the South's military has identified as a short-range ballistic missile toward the East Sea on Thursday.

The recent missile launches came as South Korea and the U.S. are set to begin their key annual Ulchi Freedom Shield exercise next week.

Pyongyang has strongly denounced the allies' drills as war rehearsals and conducted its own weapons tests around the training period in a show of protest.

Unlike how the North has usually revealed its missile launches through state media the following day or so, it has not published any reports on last week's launch.

This has raised the possibility that the launch may not have succeeded or involved the test-firing of a new type of missile, or that it could have been a longer range missile fired at a reduced range.

"It could be a repeat of last week's launch following its suspected failure and is believed to be a test-firing aimed at improving its missile capabilities," said Yang Moo-jin, a senior professor at the University of North Korean Studies.

"Given the intensifying war in Ukraine, it could also be a test to upgrade the Hwasong-11 missiles, which are designed to carry tactical nuclear warheads," Yang said.

South Korean and U.S. intelligence authorities tracked the launch since its early stage and shared information with Japan as well, maintaining a full readiness posture through cooperation between the two countries, the JCS said.

"Under the staunch South Korea-U.S. combined defense posture, our military is closely monitoring various North Korean activities and maintaining the capability and readiness to respond overwhelmingly to any provocation," it said.

South Korea's National Security Office (NSO) expressed concerns over continued missile launches since last week, urging Pyongyang to stop such provocations that are in violation of U.N. Security Council resolutions.

The NSO convened an emergency meeting with defense and military officials shortly after Wednesday's launch to assess the launch and its impact on security, and directed necessary measures, officials said.

Foreign policy officials of South Korea, the U.S. and Japan held a phone call and reaffirmed that North Korea's ballistic missile launches violate the relevant U.N. Security Council resolutions, according to Japan's foreign ministry.

The three officials -- Baek Yong-jin, director-general for Korean Peninsula policy at Seoul's foreign ministry; David Wilezol, U.S. deputy assistant secretary of state; and Takashi Ariyoshi, deputy director-general of the Asian and Oceanian Affairs bureau at Tokyo's foreign ministry — "called on North Korea to cease such provocations that threaten the peace and security of the region and the international community," it said in a press release.

The latest missile launch was also observed from an eastern coastal area in South Korea's Goseong county in Gangwon Province, located about 130 km in a direct distance from Wonsan.

The U.S. Pacific Command said in a media statement that it assesses the North's recent missile launch as not posing an immediate threat to its territory and allies.

The latest launch marked the 11th such launch by North Korea this year to date.