US to Russia: 5 countries with strongest nuclear weapon programs

The US has the largest and most advanced nuclear arsenal, with an estimated 5,800 warheads, including strategic and tactical weapons.

Russia has the second-largest nuclear arsenal, with an estimated 5,500 warheads, and a strong focus on modernizing its nuclear capabilities.

China has a rapidly modernizing nuclear program, with an estimated 350-400 warheads, and a focus on developing new delivery systems and technologies.

France has a significant nuclear arsenal, with an estimated 300-400 warheads, and a focus on maintaining its nuclear deterrence capabilities.

The UK has a smaller but still significant nuclear arsenal, with an estimated 215 warheads, and a focus on maintaining its nuclear deterrence capabilities.