On the face of it, Russia has so much to lose. Iran has been a particularly useful “strategic partner” for the Kremlin, not only sharing a disdain for Western values and influence, but also supplying the Russian military with vast squadrons of Shahed aerial drones, enabling the relentless bombardment of Ukraine.

Satellite imagery shows new air defence installations, a new loading platform for rail-based logistics, and high security fencing.

Israel has been attacking Iranian military and nuclear sites for days to, it says, stop Tehran from building a bomb.

Nine countries possess nuclear weapons, with Russia having the largest stockpile of military nuclear warheads.

MOSCOW (Reuters) -Russian President Vladimir Putin said on Wednesday that special attention in the country's new arms programme should be paid to the nuclear triad - land-based, sea-based and aircraft-launched weapons.

The Ukrainian operation was “grounds for a nuclear attack,” declared Vladmir Solovyov, a firebrand host on Russian state TV, calling for strikes on the Ukrainian presidential office in Kyiv, and beyond.

Since shortly after it was founded in 1948, Israel has been intent on building a nuclear program to ensure its survival.

The European Commission will not propose measures to limit the EU's reliance on Russian nuclear fuel this week alongside its proposals to ban Russian gas, EU energy commissioner Dan Jorgensen said on Monday.

China has an estimated 600 nuclear warheads—an increase of 100 in just one year—the Stockholm International Peace Research Institute reported.