The possession of nuclear weapons is a highly sensitive topic, and the exact details of each country's nuclear arsenal are often classified. However, it is well known that several countries possess nuclear weapons, including the United States, Russia, China, France, the United Kingdom, India, Pakistan, Israel, and North Korea.
Each of these countries has varying levels of nuclear capabilities and doctrines, and it is difficult to determine which country has the "world's deadliest" atomic weapons. It's important to note that the use of nuclear weapons is generally considered to be catastrophic and has the potential to cause significant harm to human life and the environment. Therefore, most countries with nuclear weapons have committed to disarmament and non-proliferation efforts through international treaties and agreements.