warhead

In January, North Korea claimed to fire a new intermediate-range ballistic missile tipped with a hypersonic warhead, which it said "will reliably contain any rivals in the Pacific region".

These are "dual-use weapons", meaning their warhead can be either nuclear or conventional high explosive.

The files said one incident, in August 2019, resulted in the release of "unnecessary radioactive waste" in the form of low levels of tritium, which is used in nuclear warheads.

Experts believe Iran still has centrifuges it manufactured before the war but had never installed, as well as a stockpile of uranium enriched to 20% and 60%, sufficient for 10 warheads.

Israel is the only country in the Middle East with nuclear warheads.