The US B-1B bomber conducted joint aerial drills with other US and South Korean fighter jets, South Korea's Defence Ministry said in a statement.

It said the B-1B bomber dropped Joint Direct Attack Munitions during the training while being escorted by South Korean jets, the first such bombing drill since 2017.

The JDAM bombs include “bunker-busters.” JDAM is a guidance system that converts unguided, conventional bombs into more precise, GPS-guided weapons. All US fighter jets, bombers and drones can use JDAMs, and the munitions are among the weapons systems the United States has been providing to Ukraine to help it fight Russia's invasion.

The drill is seen as a show of force against North Korea amid rising tensions over its recent launches of trash-carrying balloons toward South Korea. North Korea is sensitive to drills of bunker-buster bombs, which could threaten its leadership.

A B-1B is capable of carrying a large conventional weapons payload. North Korean has previously called the bomber's deployment proof of US hostility and responded with missile tests.

In the past week, North Korea floated hundreds of huge balloons containing manure, cigarette butts, scraps of cloth, dead batteries and reportedly dirty diapers across the border into South Korea.

In response, South Korea vowed “unbearable” retaliatory steps and suspended a fragile military deal meant to ease tensions with its northern neighbour.