What is difference between intercontinental ballistic missile and intermediate-range missile?

According to Defense Express analysts, as part of the still-absent reaction from Western countries to the attack on the Dnipro by a missile with inert warheads, some American and European publications have begun to discuss the possibility that the attack was carried out by a intermediate-range missile, not an intercontinental missile.

It is necessary to explain the difference between them and how they are classified. The benchmark is the now-defunct 1987 Intermediate-Range Nuclear Forces Treaty between the United States and the Soviet Union.

It set out the following gradation: from 1,000 to 5,500 km range - medium range, from 500 to 1,000 - short range. All of these missiles, both ballistic and ground-launched cruise missiles, were eliminated, and the parties pledged to refrain from developing them.

Thus, as the experts from Defense Express say, the difference between an intermediate-range ballistic missile (IRBM) and an intercontinental ballistic missile (ICBM) is the ability to fly more than 5,500 kilometers. An ICBM can, an IRBM cannot.

So, if we believe the Kremlin's false claims about a new missile Oreshnik, which is supposedly a intermediate-range ballistic missile, it would operate within a range of up to 5,500 km. However, everything points to the fact that Oreshnik is either the RS-26 Rubezh itself or a missile very similar to it. The RS-26 Rubezh classification raised questions because its maximum range during testing was about 5,800 km (one launch on May 23, 2012). The missile was fired from the Plesetsk Cosmodrome to the Kura test range on Kamchatka.

And it was these 5,800 km launches that allowed Russia to claim that the RS-26 Rubezh did not violate the INF Treaty and was not a medium-range missile, but an intercontinental one. Even though all three subsequent launches from the Kapustin Yar range to the Sary-Shagan range were at a much shorter range of 2,000 km.

The RS-26 Rubezh is seen as violating the INF Treaty. While Russia classifies it as an intercontinental missile, the U.S. lists it as medium-range. Designed as a medium-range missile, it serves as a successor to the RSD-10 Pioneer, freeing up ICBMs like Yars and Topol for strikes on the U.S.

For Europe, medium-range missiles are sufficient to strike any target. A range of 3,500 km allows Russia to deliver a nuclear strike on any EU location from its own territory. Medium-range missiles are also cheaper and more numerous than intercontinental ones.