Jaitley also attacked opposition leaders for their "ill-informed" criticism of the government over ceasefire violations.
"They should at least know this much as to what extent our forces are going to protect the borders," he said.
Congress Vice-President Rahul Gandhi had recently attacked Narendra Modi government over ceasefire violations and Chinese incursion, questioning its policies.
Jaitley singled out NCP leader Sharad Pawar, who had also criticised the government, and said he should have been more informed as a former defence minister.
Asked about Pakistan's motives behind the escalation, Jaitley said he would not like to speculate but firing could be a cover for infiltration and also an effort by it to precipitate tension where none existed.
"Our forces have only one option which is to respond adequately," the Defence Minister said.
He said many militants have been killed in firing since floods hit Jammu and Kashmir, an evidence of Pakistan's attempts to push more militants into Indian territory.
Asked why Pakistan is doing it now, he said the question should be put to those across the border.
