India and Pakistan appeared to be dangerously escalating their armed confrontation Thursday, as both countries said their military sites had come under attack, and heavy shelling and strikes were reported overnight on each side of their border.

The military faceoff began Wednesday, when India struck several sites in Pakistani territory — its deepest strikes inside Pakistan in decades — in retaliation for a deadly terrorist attack two weeks before.

In a sign of the international alarm that the conflict could spin out of control, U.S. Secretary of State Marco Rubio spoke with leaders from both countries Thursday and emphasized the need for “immediate de-escalation,” according to State Department accounts of the calls.India and Pakistan both continued to claim that they were not seeking an escalation in their military clash. But the reality on the ground indicated that the two nuclear-armed countries were not yet ready to take the off-ramps from their boiling tensions that had appeared to be taking shape a day before.

Latest attacks

The Indian government Thursday said it had thwarted Pakistani attempts to unleash drones and missiles at Indian military targets in more than a dozen cities and towns, many of them home to air force bases.

India said it had responded by striking Pakistan’s air defense systems and radars close to the city of Lahore — the kind of blow that often causes a military conflict to intensify, analysts said.

Pakistan accused India of continuing what it called illegal aggression and said its forces had shot down more than two dozen Indian drones that entered Pakistan’s airspace.

In the rapidly developing situation, the claims from both sides could not be independently verified.

Late Thursday, some parts of Jammu, an Indian city of about a half-million people that is part of the territory of Jammu and Kashmir, were under blackouts. The sounds of blasts and sirens could be heard across the city, as shells and drones flew overhead, according to eyewitness accounts.

“Residents are in panic and staying indoors,” said Raman Sharma, a civil activist and resident of Jammu.

India’s defense ministry, in a post on the social platform X, said military bases in Jammu and two other cities, Pathankot and Udhampur, which are close to India’s disputed Kashmir border with Pakistan, were “targeted by Pakistan using missiles and drones.”

India and Pakistan, separated from each other at the end of British colonial rule in 1947, have fought several wars, with the main flash point being their competing claims over the Himalayan region of Kashmir, which is divided between them.

The latest escalation came after a gruesome terrorist attack on the Indian side of Kashmir last month that killed 26 civilians. India accused Pakistan of being behind the attack and vowed military action. Pakistan denied the accusations and warned that it would respond in kind if it was attacked.

After a day of violence Wednesday that opened with Indian airstrikes and Pakistani claims to have shot down aircraft — and reports of dozens of deaths in total — both India and Pakistan seemed to be open to finding a way to de-escalate.

Moves to de-escalate

Even as leaders on both sides publicly struck victorious tones, Pakistani officials said security officials from both countries had made initial contact to reopen communication.

President Donald Trump expressed his willingness to help, too, as U.S. officials said they were engaging with the leaderships of both India and Pakistan to seek a resolution.

There were some hopeful signs of engagement Thursday, including a flurry of diplomatic meetings in New Delhi and Islamabad, the Pakistani capital. Top diplomats from Iran and Saudi Arabia, crucial regional players that have close ties to both of the warring countries, were in New Delhi for meetings.

But away from the halls of power, the news was of more violence as both sides appeared to be bracing for escalation.

The Indian side said it had received heavy shelling from Pakistani positions along the border areas overnight, and it reported concerted attempts by Pakistani forces to target military towns with missiles and drones.

Indian officials said they had responded forcefully, and claimed that they had targeted Pakistan’s air defense radars and systems at several locations.

The Indian defense ministry said the “Indian response has been in the same domain with same intensity as Pakistan,” suggesting that the volleys from the Pakistani side had been aimed at Indian defense installations.

“Our intention has not been to escalate matters,” said Vikram Misri, India’s foreign secretary. “We are only responding to the original escalations. And our response has been targeted, precise, controlled and measured.”