North Korea has launched several unidentified ground-based projectiles, assumed to be surface-to-ship cruise missiles, South Korea’s Joint Chiefs of Staff announced.

"North Korea fired several unidentified projectiles, assumed to be surface-to-ship cruise missiles, this morning in the direction of the East Sea from the vicinity of Wonsan, Gangwon Province," the JCS statement said, according to the Yonhap news agency.

South Korea's military added that the missiles flew about 200 kilometers (124 miles).

The missiles flew in a northeastward direction at a maximum altitude of about 2 km, Army Col. Roh Jae-cheon, a spokesman for the JCS, told reporters, according to Yonhap news.

The projectiles were detected at around 6:18 am local time and were tracked for several minutes. Jae-cheon added that the South Korean and US militaries are now trying to analyze the launch to determine what kind of missiles were used.

The JCS is “maintaining full preparedness” and has “beefed up surveillance and vigilance against the possibility of additional provocations.” President Moon Jae-in was immediately notified of the launch, the statement added.

US Missile Defense Agency: existing missile defense technology can address the current threat https://t.co/M2z83ENkO2 — RT America (@RT_America) June 7, 2017

After the reported missile test, China reiterated its call on all parties involved in the situation to exercise restraint and make an effort to stabilize the situation in the region.

Japan’s Foreign Minister Fumio Kishida said the missiles didn’t reach Japanese territorial waters or pose an immediate threat to national security. Nevertheless, he called the test a provocation and said Tokyo would not tolerate such actions.

The last time North Korea conducted a missile launch was on May 29, when it fired at least one short-range ballistic missile. The projectile, believed to be a Scud-class missile, flew around 450 kilometers before landing in the Sea of Japan, some 300 km off the Japanese islands.

Shortly afterwards, on May 30, the US conducted its first ever test of a Ground-based Midcourse Defense (GMD) interceptor with a capacity to shoot down intercontinental ballistic missiles (ICBM), that Washington said was planned “years in advance.”

US ballistic missile interceptor test ‘will only bring earlier day when US will turn into ashes’ – Pyongyang https://t.co/rEYsiJNSd5pic.twitter.com/I22739yd74 — RT (@RT_com) June 3, 2017

On Wednesday, the head of the US Missile Defense Agency (MDA) told Congress that Pyongyang’s ballistic missile tests in the last six months have become cause for concern to the US and its allies in the region.

“It is incumbent on us to assume that North Korea today can range the United States with an ICBM carrying a nuclear warhead,” Vice-Admiral James Syring, director of the MDA, told the House Armed Services Committee.

Syring however assured US lawmakers that America has the ability to defend itself against the North Korean threat, citing the successful test of the GMD interceptor. He also stated that the US plans to conduct another GMD test towards the end of 2018.

S. Korean THAAD deployment faces delay of up to a year over environmental impact probehttps://t.co/kLjTmzr3kIpic.twitter.com/JgaPym3XbW — RT (@RT_com) June 6, 2017

The Vice-Admiral also told Congress that the MDA plans to deliver 36 more Standard Missile (SM-3) interceptors to the US Navy for use on Aegis cruisers and the land-based missile defense site in Romania. Another 52 Terminal High Altitude Area Defense (THAAD) interceptors will be delivered to the US Army.

In defiance of UN resolutions, North Korea has conducted dozens of missile tests and tested two nuclear bombs since the beginning of 2016. In response, the US has increased its military power in the region and introduced additional sanctions against Pyongyang. Washington has also been pressuring China to play a more constructive role in curbing Pyongyang's missile and nuclear programs.