North Korea has refused to take regular phone calls from South Korea for a month, while stepping up criticism of the Yoon Suk Yeol government’s policy of strengthening coordination with the United States in countering and deterring escalating North Korean threats.

Pyongyang has violated the inter-Korean commitment to hold calls through the liaison and military hotlines twice a day, in the morning and afternoon. But the Kim Jong-un regime has not provided any clear explanation for why it unilaterally severed all inter-Korean communication channels since April 7.

The start of North Korea’s silence came one day after South Korea’s Unification Ministry warned that it would take necessary measures if North Korea continues illegally to use South Korean assets at the now-shuttered Kaesong Industrial Complex. North Korea remained silent during the largest field training exercises in five years, which were staged by Seoul and Washington in March and April.

North Korea has a track record of intentionally cutting off inter-Korean communication channels in order to air its grievances with South Korea.

In June 2020, North Korea destroyed an inter-Korean liaison office to protest the spread of anti-North Korea leaflets by a South Korean civic group across the inter-Korean border, leading to the severance of the communication lines.

The inter-Korean hotlines were restored in July 2021, after a 14-month suspension. Pyongyang, however, once again halted the operation of the communication channels between August and October 2021, in a backlash against regular combined military exercises between South Korea and the US.

While refusing to answer inter-Korean calls, North Korean state media has ratcheted up criticism of the Washington Declaration, claiming that North Korea should further bolster its nuclear buildup at a juncture when South Korea and the US seek to enhance the viability of the US' extended deterrence strategy.

The essence of the Washington Declaration signed by South Korean President Yoon and US President Joe Biden during the April 26 summit is to establish a Nuclear Consultative Group, which serves as a shared decision-making framework, and to enhance further the regular visibility of US strategic assets to the Korean Peninsula.

The Rodong Sinmun, the official newspaper of the central committee of the ruling Workers' Party of Korea, published a series of articles denouncing the Washington Declaration every day from April 30 to Saturday. North Korea’s most-circulated newspaper primarily targets a domestic readership. North Korean youth on Tuesday held a rally where they burned effigies of Yoon and Biden, inciting anti-US and anti-South Korean sentiments.

On Sunday, North Korea’s Uriminzokkiri, a North Korean state-controlled propaganda website that mainly targets a South Korean audience, claimed that the Yoon government’s “pro-US toadyism and submissive behavior have worsened relations with neighboring countries and had a significant impact on the South Korean economy.”

Amid simmering tensions on the peninsula, South Korea and the US have announced plans to kick off their largest-ever combined live-fire exercises later this month, marking the 70th anniversary of their alliance and the 75th anniversary of the South Korean military’s establishment.

The “combined and joint firepower annihilation drills” will take place five times from May 25 to June 15 at the Seungjin Fire Training Field in the city of Pocheon, Gyeonggi Province, according to the Defense Ministry.

A multidomain firepower demonstration intends to display the allies’ capabilities to retaliate in the event of North Korean provocations and annihilate the enemy by mobilizing South Korea and US forces and their advanced weapons, including F-35A stealth fighter jets. The allies have conducted firepower demonstrations 11 times since 1977, although the liberal Moon Jae-in government scaled down live-fire exercises.

But this year, the Defense Ministry will invite a total of 1,500 people to five firepower demonstrations to improve public confidence in the military and enhance public awareness of national security.