Explain the reasons for the arms race that began during the Cold War?

After the end of the Second World War, both countries, the USA and the USSR, intended to strengthen their position in world domination, as well as expand their zone of influence over a weakened Europe.
As a result of this, world tension arose, which could at any moment lead to the outbreak of a new world war between mega states.
Due to this, the countries constantly strived to improve their military potential, in order to strike a powerful blow in response in the event of an attack by one of the parties, and finally destroy the political enemy.