Iran claims it has built a hypersonic missile, sparking concern across the international community.
Although Tehran has not presented evidence to show a successful test of the advanced superfast weapons, Iran's opponents are concerned about a major escalation in arms.
The announcement came after Iran said that it had sent drones to Russia, but did so before the Ukraine war began in February.
What is this new generation of weaponry and who is developing it?
What are hypersonic missiles?
Hypersonic means anything that travels faster than the speed of sound, about 1,235 kilometres per hour.
A traditional ballistic missile is launched from a point, travels into the atmosphere and then returns to earth on top of the target at speeds in excess of 26,000kph. This means these missiles can hit hypersonic speeds.
But, a hypersonic missile differs from a conventional missile in that it travels much closer to the earth, eliminating the arch into the atmosphere.
They stay closer to the earth at five times the speed of sound (6,200kph) and are highly manoeuvrable, making them hard to predict, track and destroy.
While all missiles are complex technology ― it is rocket science ― making hypersonic missiles is more complex.
Making the projectile manoeuvrable and making sure it can navigate to its targets at such speeds are all difficult, but anything travelling at that speed in the Earth's atmosphere experiences extreme stress and resistance.
The technology is not new, but nations are finding ways to improve it and set it to work.
There are three main types of hypersonic weaponry: aero-ballistic, glide vehicles and cruise missiles.
Aero-ballistic systems are dropped from aircraft; hypersonic glide vehicles are launched from a rocket before gliding to a target, and hypersonic cruise missiles are powered by high-speed, air-breathing engines during flight.
John Hyten, former vice chairman of the US Joint Chiefs of Staff and former commander of US Strategic Command General, said they could enable “responsive, long-range, strike options against distant, defended, and/or time-critical threats [such as road-mobile missiles] when other forces are unavailable, denied access, or not preferred.”
Which countries have them?
China, the US and Russia are locked in an arms race to develop and deploy hypersonic weapons, while other nations are working on smaller-scale programmes.
The US said its system is designed to be used for non-nuclear warheads and therefore needs to be much more accurate than Russia and China's developing systems, which the US claimed are being designed to carry nuclear weapons.
Russia has used hypersonic missiles in conflict. In March, it struck a Ukrainian arms depot with an early version of the weapon.
North Korea's test of a hypersonic missile last year sparked concerns about the race to acquire the technology, which is led by Russia, followed by China and the US.
The US Air Force successfully tested two Lockheed Martin hypersonic missiles in July 2022, fired from a B-52 bomber.
Japan's Defence Ministry is also preparing hypersonic missiles by 2030 to boost deterrence, the Nikkei business daily reported on Thursday.
The ministry is seeking counterforce capabilities as Russia's invasion of Ukraine changed the global security environment and North Korea's series of missile launches and China's military movements threaten Japan, the report claimed.
Can they be intercepted?
The missiles are extremely hard to defend against as the flight path can be altered after launch and the speed at which they travel does not allow for much of a response time. In an effort to counter these threats, sensor programmes are being set up to monitor airspace.
Traditional ballistic missiles like ICBMs travel much higher up in the atmosphere than hypersonic gliders and so are easier to detect from the ground.
The development of the missiles and defence technology is likely to take years and cost billions.