Nuclear weapons debate
After the bombings of Hiroshima and Nagasaki, the world’s nuclear weapons stockpiles grew, and nuclear weapons have been detonated on over two thousand occasions for testing and demonstration purposes. Countries known to have detonated nuclear weapons—and that acknowledge possessing such weapons—are (chronologically): the United States, the Soviet Union (succeeded as a nuclear power by Russia), the United Kingdom, France, the People's Republic of China, India, Pakistan, and North Korea.
Nuclear weapons and Israel
However, Israel maintains a policy of deliberate ambiguity, never officially denying nor admitting to having nuclear weapons, instead repeating over the years that "Israel will not be the first country to introduce nuclear weapons to the Middle East". Israel has also declined to sign the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) despite international pressure to do so, saying that would be contrary to its national security interests.