North Korea fired multiple short-range ballistic missiles for the first time in two months on Monday as US Secretary of State Antony Blinken began his visit to South Korea.

Seoul's military said it had "detected around 0744 local time the launch of what appeared to be multiple short-range ballistic missiles," adding they flew around 300 kilometres before coming down into the East Sea, also known as the Sea of Japan.

South Korea condemned the launches as a "clear provocation" and said it was sharing information on them with the United States and Japan.

Japan's defence ministry said three missiles were launched and travelled about 350 kilometres, with a maximum altitude of 50 kilometres.

Analysts said the launches were a calculated move to grab attention as Blinken gets his trip underway.

Blinken was attending the third Summit for Democracy and met South Koeran President Yoon Suk-yeol in Seoul early on Monday. He also met his South Korean counterpart on the sidelines of the event for discussions which were likely to be dominated by efforts to counter threats from the nuclear-armed North.

Washington and Seoul wrapped up one of their major annual joint military training exercises last week, prompting angry retorts and live-fire drills from Pyongyang, which condemns all such exercises as rehearsals for invasion. (AFP/Reuters)