DPRK launched three short-range ballistic missiles toward the Sea of Japan on Saturday, reported Korea's Yonhap news agency, citing the South Korean military. 

The missiles were launched from Chunghwa County in DPRK’s North Hwanghae Province at around 8 am local time, Yonhap said, citing the South Korean Joint Chiefs of Staff (JCS).

"While strengthening our monitoring and vigilance, our military is maintaining a full readiness posture in close cooperation with the United States," the JCS said in a Saturday message, as quoted by Yonhap.

According to the Japanese Kyodo news agency, citing the Japanese Defense Ministry, the three ballistic missiles flew over a distance of 350 kilometers (217 miles), reaching a maximum altitude of 100 kilometers (62 miles).

All of the missiles landed outside Japan's exclusive economic zone. 

Earlier on Saturday, Yonhap reported that Pyongyang test-fired one ballistic missile toward the Sea of Japan, while Japanese media reported on two suspected launches.

Japanese Prime Minister Fumio Kishida instructed relevant ministries to carry out a detailed analysis of Pyongyang's test launch and a crisis response center has been set up under the Prime Minister's office, according to Japanese media reports. 

Tokyo has expressed protest to Pyongyang over the Saturday test-firing, according to Kyodo.

This year, DPRK has conducted nearly 40 test launches, firing approximately 70 missiles, including an intercontinental ballistic missile test in November.

Pyongyang's latest test-firing on Saturday followed South Korea's test-firing of a solid-fuel carrier rocket on Friday as part of its efforts to strengthen space-based reconnaissance capabilities, according to South Korea's Defense Ministry.

Earlier this month, in light of South Korea's provoking military drills with the participation of Japan and the US in the Korean Peninsula on December 5, Seoul's Joint Chiefs of Staff said in a statement that DPRK fired about 130 artillery shells at 2:59 pm (0559 GMT) from two distinct sites, one on the DPRK's east coast and one on the west coast. 

According to a statement issued by the South's military, some of the shells landed in a "buffer zone" near the sea border in what Seoul said was a violation of a 2018 inter-Korean agreement designed to ease tensions between the two countries.

But none of the shells crossed the Northern Limit Line, which is the de facto maritime border, the statement added. 

"Several warnings" have been issued over the barrage, the statement said, adding that "our military is strengthening its readiness posture in preparation for emergencies while tracking and monitoring related developments under close cooperation between South Korea and the US."