India is not the only one who decides who carried out the terrorist operation and whether the targets were terrorist camps or military camps. India took a very hasty position by accusing Pakistan of planning the terrorist operation and subsequently took escalatory steps. My analysis is that India would not have done this without external incitement from powers with interests far from the reality of the war between the two countries. The Western powers believed that the weapons they sold to India would be able to end the crisis in record time, in a clear challenge to the Chinese weapons possessed by Pakistan. What happened was a true farce that revealed the extent of the development of the Chinese military industry and the backwardness of the latest Western weapons.
In short, India is the one who insisted on entering into a military confrontation without regard for any diplomatic procedures or rational logic. This is true folly that has plunged the country into a crisis that no one knows how or when it will end. Usually, no one emerges victorious from these wars, especially with two nuclear powers capable of setting fire to the entire planet. Therefore, I accuse the Indian government of pushing towards war and taking a huge risk that will cost India more than expected.
They entered into a country and killed the civilians then what do you expect a country to react?
Investigations needed to reveal the full story of who is behind this. But It is proven multiple times that Pakistan sponsored terrorism to attack India for example 2008 blast carried out by LeT organization operating in Pakistan and US confirmed it too and then in 2016 and then in 2019 and a few hundred times so we need to turn back the history to know the full story.

And I am asking again if the same thing happened in the USA how they will react? Anyone can answer my question.

Please feel free to.