America develops nuclear weapons 24 times more powerful than the atomic bomb in Hiroshima

In a press release, the Pentagon revealed that it hopes to get approval and funding from Congress to develop the weapon. The bomb, called the B61-13, will have a similar yield to the B61-7 it is intended to replace. The B61-7 has a maximum yield of 360 kilotons, 24 times more powerful than 'Little Boy,' the 15 kiloton bomb that leveled Hiroshima.

The B61-7 is not the most powerful nuclear weapon in the US arsenal. That title belongs to the B83, a thermonuclear gravity bomb with a yield of 1.2 megatons of TNT. The B83 replaced the even more powerful B53, which had a yield of 9 megatons and was retired in 2011.

However, the most powerful nuclear bomb ever tested was built by the Soviet Union. Detonated in 1961, the 'Tsar Bomba' had an estimated yield of 58 megatons, equivalent to more than 1,500 Hiroshima bombs.

“Today’s announcement reflects the changing security environment and evolving threats from potential adversaries,” said John Plumb, Assistant Secretary of Defense for Space Policy. “The United States has a responsibility to continue to assess and deploy the capabilities we need to credibly deter and, if necessary, respond to strategic attacks and reassure our allies.”

The announcement came less than two weeks after the US conducted an underground explosion at its Nevada nuclear test site, the first such explosion since the early 1990s. The explosion occurred just hours after Russia's State Duma (lower house) passed a bill to withdraw its ratification of the 1996 Comprehensive Nuclear-Test-Ban Treaty (CTBT). The treaty was never ratified by the US.

Russian President Vladimir Putin said that if the US continues nuclear testing, which the Russian leader believes Washington could do as part of its arsenal modernization, Moscow will make a similar move./.