Minutes before Indian defence officials announced a ceasefire with Pakistan, US President Donald Trump on Saturday declared to the world with a post on X how his administration had mediated with both countries to end the heightened military conflict.

Confirming the involvement of the US in the de-escalation of the conflict between the nuclear-armed neighbours, the New York Times on Sunday reported that Trump officials grew very concerned that the attacks could 'spiral out of control', especially after "explosions hit the Nur Khan air base in Rawalpindi"... which is not far away from "the division that manages Pakistan's nuclear arsenal".

The newspaper said initially the Trump officials had dismissed India's response to the Pahalgam attack and the Pakistani retaliation as “fundamentally none of our business,” they changed the tack once they realised that the conflict "might quickly go nuclear".

"...Within 24 hours (of Vice-President JD Vance dismissing it as not America's fight) , he and Marco Rubio, in his first week in the dual role of national security adviser and secretary of state, found themselves plunged into the details," the NYT report said.

"What drove Vance and Rubio into action was evidence that the Pakistani and Indian Air Forces had begun to engage in serious dogfights, and that Pakistan had sent 300 to 400 drones into Indian territory to probe its air defences. But the most significant causes for concern came late Friday, when explosions hit the Nur Khan air base in Rawalpindi, the garrison city adjacent to Islamabad," the report said.

"The base is a key installation, one of the central transport hubs for Pakistan’s military and the home to the air refuelling capability that would keep Pakistani fighters aloft. But it is also just a short distance from the headquarters of Pakistan’s Strategic Plans Division, which oversees and protects the country’s nuclear arsenal, now believed to include about 170 or more warheads," report by David E SangerJulian E Barnes and Maggie Haberman said.

"One former American official long familiar with Pakistan’s nuclear programme noted that Pakistan’s deepest fear is of its nuclear command authority being decapitated. The missile strike on Nur Khan could have been interpreted as a warning that India could do just that," the report said.

After this strike, the Trump administration grew concerned that "...messages to de-escalate were not reaching top officials on either side". Interventions by Saudi Arabia and the United Arab Emirates had little effect.

"So Vance called Prime Minister Narendra Modi directly...pressed him to consider alternatives to continued strikes, including a potential off-ramp that US officials thought would prove acceptable to the Pakistanis. Modi listened but did not commit to any of the ideas," the report said.

Rubio talked to Pakistan's army chief Gen. Syed Asim Munir. The NYT report, quoting State Department sources, said he also spoke to Pakistan’s foreign minister Ishaq Dar and India’s external affairs minister S Jaishankar.

"A senior Pakistani intelligence official...credited the involvement of the Americans...and in particular Rubio’s intervention, for sealing the accord. "India, in contrast, did not acknowledge any US involvement," the report noted.