With U.S. Vice President Kamala Harris' set to visit to Seoul Thursday, North Korea fired two short-range ballistic missiles off its east coast Wednesday, the South Korean military said.

The launch came two days after South Korea and U.S. forces conducted a military drill in waters off the South's east coast involving an aircraft carrier. On Sunday, North Korea fired another ballistic missile toward the sea off its east coast.

Wednesday's missiles were launched from the Sunan area of Pyongyang, the North Korean capital, between 6:10 p.m. and 6:20 p.m. (9:10 a.m.-9:20 a.m. GMT), South Korea's Joint Chiefs of Staff said.

They flew about 360 kilometers (225 miles), reaching an altitude of 30 kilometers (19 miles) and a maximum velocity of Mach 6 (7,450 kph), they said, adding a detailed analysis was underway.

"North Korea's provocations will further strengthen the South Korean-U.S. deterrence and response capability, and only deepen North Korea's isolation from the international community," the Joint Chiefs said in a statement.

South Korea's national security council held an emergency meeting and condemned the test, vowing to continue building an "overwhelming" capacity to deter North Korea, President Yoon Suk-yeol's office said in a separate statement.

North Korean state media did not mention the reports of the latest launches, but its leader Kim Jong Un has said its development of nuclear weapons and missiles are meant to defend North Korea against U.S. threats.

Japan's coast guard also reported a suspected ballistic missile test, which its minister of state for defense, Toshiro Ino, condemned as "unacceptable". He said Pyongyang's repeated missile launches imperiled Japanese and international security.

Following a stop in Japan, Harris will land in the South Korean capital and visit the heavily fortified Demilitarised Zone (DMZ) between the neighbors on Thursday.

In a speech hours earlier aboard the destroyer USS Howard in the Japanese city of Yokosuka, Harris called Sunday's missile launch part of an "illicit weapons program which threatens regional stability and violates multiple U.N. Security Council resolutions".

The U.S. Indo-Pacific Command said the latest launch highlights the "destabilizing impact" of the North's unlawful weapons programs.

A U.S. State Department spokesperson also condemned the test as a regional threat but said Washington remained committed to a diplomatic approach and urged Pyongyang to engage in dialogue.

North Korea has tested missiles at an unprecedented pace this year, while this week's joint drill is a show of force intended to warn against what could be Pyongyang's first nuclear test since 2017.

The isolated country has completed preparations for a nuclear test, a window for which could open between China's party congress in October and the U.S. mid-term elections in November, South Korean lawmakers said on Wednesday.