The fighting between India and Pakistan intensified sharply on Saturday, with both sides targeting air bases and military sites, and each blaming the other for striking first.

Pakistan said India had targeted at least three of its air bases with air-to-surface missiles in the early hours of Saturday, including Nur Khan, a key air force installation near the capital, Islamabad. Witnesses in the city of Rawalpindi, where Nur Khan is located, reported hearing at least three loud explosions, with one describing a “large fireball” visible from miles away.

Within hours, Pakistan said it had retaliated using short-range surface-to-surface missiles against several locations in India, including the Udhampur and Pathankot air bases and a missile storage facility. “An eye for an eye,” the Pakistani military said in a statement.

India, however, said it had struck several Pakistani military targets, two of them radar sites, in response to a wave of Pakistani attacks on 26 locations using drones, long-range weapons and fighter planes. There was “limited damage” to equipment and personnel at four air force bases, Vyomika Singh, an Indian military spokeswoman, said at a news conference on Saturday.

“It is Pakistani actions that have constituted provocation and escalation. In response, India has defended and reacted in a responsible and measured fashion,” India’s foreign secretary, Vikram Misri, said.

Between the claims and counter claims, it was increasingly clear that the night involved some of the heaviest military engagement from both sides since the armed confrontation began on Wednesday.