What is an intercontinental ballistic missile?

An intercontinental ballistic missile (ICBM) is a guided missile that is designed to deliver nuclear warheads, although they could also deliver other payloads.

According to the Federation of American Scientists, ICBMs have a minimum range of 5,500 kilometers (3,400 miles), with maximum ranges varying from 7,000 to 16,000 kilometers.

Russia, the United States, China, and India have, until now, been the only countries currently known to possess land-based ICBMs. Israel has also tested ICBMs, although it has been secretive about actual deployment. The US, Russia, United Kingdom, France, India and China are also current operators of ICBMs that can be launched from submarines.

North Korea's state media announced Tuesday that Pyongyang had

successfully launched an ICBM for the first time During its 39-minute flight, the rocket traveled 933 kilometers (580 miles), and reached a cruising altitude of 2,802 kilometers, the report said.

The rogue state said its launch was conducted at the sharpest possible angle, and that it was now capable of striking any country in the world.

The United States later confirmed North Korea test launched an ICBM, saying that it believed it was a two staged version.

ICBMs are much faster and have a greater range than other types of ballistic missiles, which include intermediate-range ballistic missiles (IRBMs), medium-range ballistic missiles (MRBMs), short-range ballistic missiles (SRBMs) and tactical ballistic missiles (TBMs).

The missiles can also be launched in different ways: from underground missile silos, submarines, heavy trucks, or mobile launchers on rails.

North Korea has stepped up its missile tests over the past year, and analysts say it is years away from having a nuclear-tipped ICBM. On its website, the Federation of American Scientists says ICBMs can create a real problem because they enable a country to "break out of a regional context and move toward potential global impact."

"Regardless of the origin of a conflict, a country may involve the entire world simply by threatening to spread war with an ICBM."

The first ICBMs were deployed by the Soviet Union in the late 1950s, with the US following soon afterwards. Early versions of the missiles had limited precision, meaning they could only effectively be used against large targets, like cities. Accuracy improved dramatically in later models, allowing the weapons to successfully strike the smallest of targets. Modern designs tend to be smaller and lighter than their ancestors. They also allow a single missile to carry multiple warheads, each of which can be sent in a different direction to strike a different target.