The latest action by North Korea came as US President Joe Biden’s national security adviser, Jake Sullivan, was in Tokyo for meetings with his Japanese and South Korean counterparts.

In a meeting with South Korea’s national security adviser, Cho Tae-yong, and Japan’s national security adviser Takeo Akiba today, the three discussed North Korea’s missile programme and confirmed that they would work closely together to get Pyongyang to abandon its nuclear weapons, according to a readout of the meeting released by Japan.

South Korean president Yoon Suk-yeol watched as several thousand South Korean and US troops took part in joint live-fire exercises today, in the latest show of force that the allies say is necessary to deter North Korea.

A spokesman for North Korea’s ministry of national defence said the drills were escalating the military tension in the region and its forces would sternly respond to “any kind of protests or provocations by enemies”.

Pyongyang unsuccessfully tried to launch a spy satellite late last month, in its first satellite launch since 2016, with the rocket booster and payload plunging into the sea.

North Korea’s ballistic missile and nuclear weapons programmes are banned by UN Security Council resolutions that have sanctioned the country.

Diplomatic efforts to reduce tensions or persuade Pyongyang to abandon its nuclear arsenal have been stalled.

South Korea sued North Korea on Wednesday for US$35 million in compensation for a liaison office that North Korea blew up in 2020, in a case highlighting the breakdown of ties between the neighbours as the North presses on with its weapons programmes.