Pakistan’s army said it struck several Indian military sites early Saturday in retaliation for India’s missile strikes on airbases, a significant escalation in the conflict between the two nuclear-armed neighbors.

The army said in a statement it hit Indian airbases and other military sites in the Indian-controlled part of Kashmir region and in Punjab state. India’s Ministry of Defense didn’t immediately respond to Pakistan’s claims, but local media in India reported that the strikes were intercepted.

The tit-for-tat military action is now in its fourth day, with tensions between the two nations at their most dangerous levels in years, marked by both sides shooting down missiles and drones over densely populated cities.