The incident marks the North’s seventh ​ballistic missile launch this year and its fourth in April.

“As the ​US is focused on Iran, the North sees this as a ⁠golden time to upgrade their nuclear power and missile capability,” Lim ​Eul-chul, a professor at Kyungnam University, said.

South Korea’s presidential office said it had ​held an emergency security meeting, media reports said.

Such tests violate UN Security Council resolutions against the North’s missile programme.

Pyongyang rejects the UN ban and says it infringes its ​sovereign right to self-defence.

The missiles were fired near the city of Sinpo ​on North Korea’s east coast at around 6.10am, South Korea’s military said in ‌a ⁠statement.

Japan’s government posted on social media that the ballistic missiles are believed to have fallen near the east coast of the Korean Peninsula, and no incursion into Japan’s exclusive economic zone has been confirmed.

The launches come as China ​and the United ​States prepare for ⁠a summit in mid-May where US President Donald Trump and Chinese President Xi Jinping are expected to discuss North ​Korea.

North Korea has made “very serious” advances in its abilities ​to turn ⁠out nuclear weapons, with the probable addition of a new uranium enrichment facility, International Atomic Energy Agency chief Rafael Grossi said on Wednesday.

In late March, North Korean ⁠leader ​Kim Jong Un said Pyongyang’s status as a ​nuclear-armed state was irreversible and expanding a “self-defensive nuclear deterrent” was essential to national security.