As tensions between the US and North Korea continue to rise amid heightened concerns over a potential nuclear war, the US appears to be ramping up its nuclear defence strategy. The US military has reportedly developed microwave weapons – called Counter-electronics High Power Microwave Advanced Missile Project (CHAMP) – that could knock out North Korean missile control systems.

The microwave weapons have reportedly been designed to be fitted onto air-launched missiles, delivered by US B-52 bombers. The bombers can reportedly fly CHAMPs over contested airspaces, flying at low altitudes, so the weapons can emit sharp pulses to disable nearby electronic systems.

Citing unspecified sources at the US Air Force, NBC News reported that the microwave weapons, which are currently not operational, could be ready for use within days. CHAMP was reportedly discussed at a White House meeting relating to North Korea in August, hinting at the possibility of these weapons being used in an actual assault.

What are CHAMPs?

According to NBC News' report, the US Air Force Research Laboratory began working on CHAMP in 2009 and by 2012 the weapon was ready for operational testing. In a mock situation, a B-52 reportedly launched the CHAMP-carrying missiles over the Utah Test and Training Range, which was rigged with buildings containing "representative WMD production equipment" found in North Korea and Iran.

The NBC News report added that the low-flying missiles are now "capable of flying into a contested area and disabling an adversary's electronic systems", according to a December 2016 Air Force Research Laboratory document.

"These high-powered microwave signals are very effective at disrupting and possibly disabling electronic circuits," Mary Lou Robinson, who heads development of the weapons at the Air Force Research Laboratory, told NBC News.

"It absolutely did exactly what we thought it was going to do," said Robinson, explaining the success of the 2012 test. "We had several different target classes in those facilities, and we predicted with almost 100 percent accuracy ... which systems were going to be affected, which systems failed, and how."

Using such weapons would likely avoid the use of deadly force in a combat scenario, while ensuring that the adversary's control systems are paralysed.

However, CHAMP has a limitation – the microwave weapon's emitter does not have a wide range. The weapon would have to get "close" to the target for electronic systems to be disabled.

A weapon like CHAMP would neutralise a North Korean nuclear threat even before Pyongyang had the opportunity to fire a missile. However, in the event that a missile has already been fired, it is unclear if CHAMP would be of any use.

According to latest reports, the recently tested Hwasong-15 broke up upon re-entry. However, some experts believe that North Korea could be preparing for more tests soon.