Last week, North Korea conducted one of its most provocative weapons demonstrations in years by flight-testing for the first time an intercontinental ballistic missile (ICBM) powered by solid fuel. It is considered a more mobile, harder-to-detect weapon and could directly target the continental US.

South Korea’s navy said Monday’s three-way drills took place in international waters off the country’s eastern coast and focused on mastering procedures for detecting, tracking and sharing information on incoming North Korean ballistic missiles. The one-day naval exercise involved an Aegis destroyer from each country.

“The drills’ goal is to improve our response capabilities against ballistic missiles and strengthen our ability to conduct joint operations as North Korea’s nuclear and missile threats continue to escalate,” Jang Do-young, a spokesperson for South Korea’s navy, said at a news briefing.

South Korea and the US also launched separate bilateral drills on Monday involving some 110 warplanes, including advanced F-35 fighter jets, that will continue through April 28.

The two sets of exercises could trigger a belligerent response from Pyongyang, which views the US’s military drills with its Asian allies as invasion rehearsals. North Korea has used such drills as a pretext to accelerate its own weapons development, creating a tit-for-tat cycle that has raised tensions in recent months.

Later on Monday, Ri Pyong Chol, a North Korean army marshal and close associate of leader Kim Jong Un, warned that the US should “stop at once its political and military provocations”.

“If the US persists in the acts of endangering the security environment on the Korean Peninsula in disregard of the repeated warnings by [North Korea], the latter will take necessary actions to expose the former to a clearer security crisis and insurmountable threats,” Ri said in a statement carried by state media.

Without mentioning the drills that began on Monday, Ri accused the US and South Korea of having staged a series of large-scale joint military exercises simulating a preemptive nuclear strike and all-out war against North Korea.

He also criticised the US for calling for a meeting of the United Nations Security Council to discuss North Korea’s solid-fuel ICBM launch, saying his country was exercising its right to self-defence.

Security Council resolutions ban North Korea from engaging in any ballistic activities. But the council has failed to impose new sanctions on North Korea despite the series of ballistic missile tests it began early last year. China and Russia, which are both veto-wielding members, have opposed the sanctions.

North Korea’s unprecedented run of weapons tests has so far involved more than 100 missiles of various ranges fired into the sea since the start of 2022, as it attempts to build a nuclear arsenal that could threaten its neighbours and the US.

Experts say Kim wants to pressure the US into accepting North Korea as a legitimate nuclear power and hopes to negotiate an easing of sanctions from a position of strength.

South Korea and the US in March conducted their biggest field exercises in years and have also held separate naval and aerial drills involving an aircraft carrier battle group and nuclear-capable B-52 bombers.

North Korea’s growing nuclear threat has also led South Korea and Japan to increase their security cooperation and mend ties strained by history and trade disputes.

On Monday, South Korea and Japan held their first security meeting of senior diplomats and defence officials following a five-year hiatus. During the meeting, Seoul and Tokyo discussed North Korea’s nuclear programme and trilateral cooperation with the US, according to Seoul’s defence ministry.

In a statement, Japan’s Joint Chiefs of Staff stressed the need to strengthen trilateral cooperation as the “security environment surrounding Japan increasingly becomes severe” because of Pyongyang’s missile activities.

For the 11th straight day on Monday, North Korea did not respond to South Korean checkup calls on a set of cross-border inter-Korean hotlines, South Korean officials said, raising concerns about potential incidents. Communications on those channels are meant to prevent accidental clashes along the rivals’ sea borders or to arrange talks.

On Saturday, a South Korean naval vessel fired warning shots to repel a North Korean patrol vessel that temporarily crossed the countries’ disputed western sea boundary while chasing a Chinese fishing boat.

Such issues have been worsened by pandemic-related border restrictions that disrupted trade with China, its main ally and economic lifeline.

Desperate for tangible economic achievements, Kim’s government has prioritised construction and agricultural projects, which are less dependent on external trade. Industrial production, meanwhile, remains decimated by international sanctions and COVID-linked border shutdowns.

The North’s official Korean Central News Agency (KCNA) said on Monday that Kim attended an event over the weekend celebrating the building of 10,000 new homes in a district of Pyongyang. The project is part of broader plans to supply 50,000 new homes to the capital under a five-year national development plan that runs through 2025.

During Sunday’s event, Kim called the housing project a “long-cherished plan” aimed at providing his people with “more stable and civilised living conditions”, the KCNA said.

North Korea has a severe shortage of quality housing that deepened over decades of economic decay. But living conditions are much better in Pyongyang, where Kim has pushed huge development projects that upgraded housing for elites.