A US B-1B strategic bomber is set to participate in the joint air drills with South Korea on Saturday, according to a Defense Ministry official in Seoul to AFP, which is demonstrated as a show of force after North Korea's missile launches. 

Pyongyang's launches on Wednesday and Thursday comprised an intercontinental ballistic missile and one that allegedly landed within South Korean territory for the first time since the Korean War ended in 1953.

In response, the US and South Korea warned that the succession of launches could lead to a "nuclear test" by North Korea, and have prolonged their largest-ever air force drills until Saturday.

As a South Korean Defense Ministry official reported to AFP, a US Air Force B-1B strategic bomber would participate on the last day of exercises, dubbed Vigilant Storm, which was scheduled from Monday to Friday this week. "B-1B is scheduled to participate in the afternoon training," the official said, without providing further details.

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The display of force came a day after South Korea scrambled fighter jets in response to what the South Korean military claims were the mobilization of 180 North Korean warplanes.

Pyongyang has increased missile launches in response to US-South Korean air drills. Such drills have historically enraged North Korea, which it regards as practice for an invasion.

It had described Vigilant Storm as "an aggressive and provocative military drill targeting" North Korea. It warned that if it continued, the US and South Korea would "pay the most horrific price in history."

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Pyongyang has previously been enraged by the deployment of US strategic weaponry such as B-1B bombers and aircraft carrier strike groups to and near the Korean peninsula at times of heightened tension.

While the B-1B no longer carries nuclear weapons, the US Air Force describes it as "the backbone of America's long-range bomber force," capable of striking anywhere in the world.

The United States on Friday assailed China and Russia at the UN Security Council for having "enabled" North Korea. US Ambassador Linda Thomas-Greenfield dismissed South Korean criticism of the drills as North Korean "propaganda", claiming that they presented no threat to other countries.