TOKYO — North Korea did not answer South Korea's phone calls via liaison and military hotlines for the second consecutive day Wednesday, Yonhap News Agency reported.

As the South and the US began a preliminary military drill on Tuesday, the calls via the inter-Korean liaison office and military communication channels in the eastern and western border regions went unanswered at 9:00 a.m. (0000 GMT), after the North began to shun their regular calls from Tuesday afternoon, according to military officials.

The disconnection followed a series of angry statements from Pyongyang after South Korea and the US began a four-day preliminary training in the run-up to the main combined exercise set to kick off next week.

Kim Yong-chol, a senior North Korean official, issued a statement earlier in the day, saying that the North will make the South "realize by the minute what a dangerous choice they made and what a serious security crisis they will face because of their wrong choice."

On Tuesday, Kim Yo-jong, the sister of Kim Jong-un, also bristled at South Korea and the US over the exercise, vowing to strengthen the country's national defense and preemptive strike capabilities "for rapidly countering any military actions against us."

The inter-Korean communication lines were restored late last month following a yearlong severance after South Korean President Moon Jae-in and North Korean leader Kim Jong-un agreed to improve their chilled ties amid little progress in nuclear negotiations.

The drills have increased tensions weeks after the hotlines were restored. Kim Yo-jong said the North would strengthen its pre-emptive strike capabilities.

The two Koreas remain technically at war after a conflict between the two sides ended in 1953 with an armistice, rather than a peace treaty. They typically check in with each other twice a day over two hotlines.

North Korea cut the lines in June 2020 as relations soured following a failed peace summit. Shortly afterwards, North Korea blew up an inter-Korean border office that had been built to improve communications.

In a statement published by state media, Kim Yo-jong said the latest drills were "the most vivid expression of the US hostile policy" towards North Korea and "an unwelcoming act of self-destruction for which a dear price should be paid".

A spokesperson for the South Korean presidential office told Reuters news agency that it would monitor the North's moves instead of "jumping to conclusions." — Agencies