North Korea has fired at least one ballistic missile into the sea, South Korea’s military says.

The joint chiefs of staff on Saturday did not say what type of missile was launched or how far it flew.

The launch came a day after North Korea’s foreign ministry threatened to take “unprecedentedly” strong action against its rivals after South Korea announced a series of planned military exercises with the US aimed at sharpening their response to the North’s growing threats.

North Korea is coming off a record year in weapons demonstrations with more than 70 ballistic missiles fired, including intercontinental ballistic missiles with potential range to reach the US mainland.

The North also conducted a slew of launches it described as simulated nuclear attacks against South Korean and US targets in response to the allies’ resumption of large-scale joint military exercise that had been downsized for years.

The North Korean statement on Friday accused Washington and Seoul of planning more than 20 rounds of military drills this year, including large-scale field exercises, and described its rivals as “the arch-criminals deliberately disrupting regional peace and stability”.

The statement came hours after South Korea’s defence ministry officials said Seoul and Washington would hold an annual computer-simulated combined training in mid-March.

The 11-day training would reflect North Korea’s nuclear threats, as well as unspecified lessons from the Russia-Ukraine war, according to Heo Tae-keun, South Korea’s deputy minister of national defence policy.

Mr Heo said the two countries will also conduct joint field exercises in mid-March that would be bigger than those held in the past few years.

South Korea and the US will also hold a one-day tabletop exercise next week at the Pentagon to sharpen a response to a potential use of nuclear weapons by North Korea.

The exercise, scheduled for Wednesday, would set up possible scenarios where North Korea uses nuclear weapons, explore how to cope with them militarily and formulate crisis management plans, South Korea’s defence ministry said.