Pakistan said it called a meeting on Saturday of the top body that oversees its nuclear arsenal after it launched a military operation against India early in the morning, targeting multiple bases including a missile storage site in northern India.

The Indian army said after the attacks that Pakistan was continuing its “blatant escalation” with drone strikes and using other munitions along India’s western border, and that its “enemy designs” would be thwarted.

Five civilians were killed in the attacks in the Jammu region of Indian Kashmir, regional police said.

Diplomatic calls for de-escalation, including by the United States, intensified as the nuclear-armed neighbours ramped up their worst fighting in three decades.

Pakistan said that, before its offensive, India had fired missiles at three air bases, including one close to the capital, Islamabad, but Pakistani air defences intercepted most of them.

Pakistan’s military also said the prime minister had called a meeting of the National Command Authority, a top body of civilian and military officials that oversees decisions on its nuclear arsenal.

Analysts and diplomats have long feared that conflict between the arch-rivals could escalate into the use of nuclear weapons, in one of the world’s most dangerous and most populated nuclear flashpoint regions.

Pakistan’s planning minister Ahsan Iqbal said the escalation was a test for the international community.

“We would hate to see that (nuclear) threshold being breached,” he said.

US Secretary of State Marco Rubio called Pakistan’s Army Chief Asim Munir on Friday morning, according to the US State Department.

“He continued to urge both parties to find ways to de-escalate and offered US assistance in starting constructive talks in order to avoid future conflicts,” said State Department Spokesperson Tammy Bruce.

Locked in a longstanding dispute over Kashmir, the two countries have engaged in daily clashes since Wednesday when India launched strikes inside Pakistan on what it called “terrorist infrastructure”. Pakistan vowed to retaliate.

The meeting of the National Command Authority signalled an alarming escalation, analysts said.

“It is a soft nuclear signal but also well in line with Pakistan’s nuclear doctrine of first use and realistically reflective of where we are on the escalation ladder - which is pretty high up, after multiple duels between both sides, and also lacking in precedent,” said Asfandyar Mir, Senior Fellow for South Asia at the Stimson Center.

An Indian army statement on X said multiple armed drones were spotted flying over the holy city of Amritsar in India’s Punjab state and were destroyed by its defence units.

Pakistan’s planning minister said in a broadcast interview that it was not targeting civilians and would only target locations that had been used for action against Pakistan.

The Indian defence and foreign ministries would jointly brief the media at 10:30 a.m. (0500 GMT), the foreign ministry said in an advisory to the media.

Pakistan’s information minister said in a post on social media site X that the military operation was named “Operation Bunyanun Marsoos”. The term is taken from the Koran and means a firm, united structure.

“BrahMos storage site has been taken out in general area Beas,” Pakistan’s military said in a message to journalists, adding that the Pathankot airfield in India’s western Punjab state and Udhampur Air Force Station in Indian Kashmir were also hit.

Sounds of explosions were reported in India’s Srinagar and Jammu, where sirens sounded, a Reuters witness said.

“India through its planes launched air-to-surface missiles ... Nur Khan base, Mureed base and Shorkot base were made targets,” Pakistan military spokesman Lieutenant General Ahmed Sharif Chaudhry said in a late-night televised statement.

The chief minister of Indian Kashmir Omar Abdullah said in a statement a local administration official had been killed by shelling in Rajouri, near the line of control that divides the contested region.

One of the three air bases that Pakistan said were targeted by India is in the garrison city of Rawalpindi, just outside the capital Islamabad. The other two are in Pakistan’s eastern province of Punjab, which borders India.

The Pakistani military spokesman said only a few missiles made it past air defences, and those did not hit any “air assets”, according to initial damage assessments.

India has said its strikes on Wednesday, which started the latest clashes between the countries, were in retaliation for a deadly attack on Hindu tourists in Indian Kashmir last month.

Pakistan denied India’s accusations that it was involved in the tourist attack. Since Wednesday, the two countries have exchanged cross-border fire and shelling, and sent drones and missiles into each other’s airspace.

Much of the fighting on Friday was in Indian Kashmir and states bordering Pakistan. India said it shot down Pakistani drones.

The Group of Seven countries on Friday urged maximum restraint and called on the two countries to engage in direct dialogue. The United Kingdom’s High Commissioner to Pakistan, Jane Marriott, said in a statement on social media platform X that they were monitoring the developments closely.

Sounds of explosions were also heard in the eastern Pakistani city of Lahore and the northwestern city of Peshawar, as the fighting threatened to spread.

At least 48 people have been killed since Wednesday, according to casualty estimates on both sides of the border that have not been independently verified.