Which soviet union action was a response to the establishment of the north atlantic treaty organization?

The North Atlantic Treaty Organization (NATO) was an alliance made between the United States and their allies right after World War II. This included countries such as Belgium, Canada, Norway, the United Kingdom, and Denmark. In response, the Soviet Union created the Warsaw Pact with their alliances. This included Albania, Bulgaria, and Romania. These alliances set the stage for the Cold War, a battle of ideologies between the US and Soviet Union for the next 30 years.