North Korea has fired an unidentified ballistic missile, Seoul's military said, in what was Pyongyang's third launch in less than a week just hours after US Vice President Kamala Harris left South Korea.
"North Korea fired an unidentified ballistic missile into East Sea," Seoul's Joint Chiefs of Staff said in a statement, referring to the waters more commonly known as the Sea of Japan.
Japan's coast guard also confirmed a possible ballistic missile launch from North Korea, citing information from Tokyo's defence ministry.
Ms Harris, who landed at Osan airbase after a trip to Tokyo to attend the state funeral of assassinated former Japanese prime minister Shinzo Abe, first met South Korea's President Yoon Suk-yeol.
She then visited the heavily fortified Demilitarised Zone that separates North and South Korea, a move that could infuriate Pyongyang.
She said that the US seeks a world where North Korea poses no threats, as the country "has a brutal dictatorship, unlawful weapons programme and human rights violations".
The trip was aimed at strengthening the security alliance with Seoul.
North Korea branded US House Speaker Nancy Pelosi the "worst destroyer of international peace" when she visited the border in August.
North Korea has conducted two banned ballistic missile launches this week ahead of Ms Harris' arrival - part of a record-breaking streak of weapons tests so far this year.
Speaking aboard a American destroyer at a naval base before she left Japan, the US Vice President accused North Korea of threatening regional stability with fresh missile launches, denouncing their "illicit weapons programme".
South Korean and US officials have been warning for months that North Korean leader Kim Jong Un is preparing to conduct another nuclear test, with the South's spy agency saying it could come as early as next month, after China's Communist Party Congress.
The United States and South Korea are conducting a large-scale joint naval exercise this week in a show of force against growing North Korean provocations.
With President Yoon, Ms Harris is set to discuss the countries' long-standing security alliance, their growing economic and technology partnership, and a range of other regional and global issues.
Seoul's is likely to raise its concerns over a new law signed by US President Joe Biden which removes subsidies for electric cars built outside of America, hitting Korean automakers like Hyundai and Kia.
