North Korea has launched three missiles, one of which is believed to have long-range capabilities, into the sea off its east coast, according to the South Korean military, just hours after Joe Biden concluded his first trip to Asia as US president.

South Korea's Joint Chiefs of Staff said in a statement that the missiles were launched from the capital's Sunan area and flew toward waters off the North's eastern coast between 6h am and 7h am on Wednesday. They claimed that one, thought to be an intercontinental ballistic missile, flew 360 kilometers at a maximum altitude of 540 kilometers.

Officials in Japan said the missiles appeared to have landed outside the country's exclusive economic zone, but there had been no reports of damage to ships or aircraft so far.

In response to the launches, South Korea and the United States launched missiles on Wednesday in response to North Korea's earlier-in-the-day ballistic missile test, according to the Yonhap news agency, citing South Korea's Joint Chiefs of Staff. The South Korean military has also dispatched around 30 F-15K fighter planes.

South Korean Foreign Minister Park Jin and US Secretary of State Antony Blinken agreed to collaborate on a new UN sanctions resolution in response to the launches, according to media reports.

North Korea has conducted 17 missile launches this year, including the first full-range test of intercontinental ballistic missiles since 2017.

The latest test comes just days after Biden visited South Korea and just hours after he returned to Washington from his trip to Japan.