India and Pakistan agreed to an immediate ceasefire on Saturday, unexpectedly halting the worst fighting in decades between the nuclear-armed neighbors, just when their tit-for-tat strikes appeared to be spiraling out of control.

President Trump also announced the cease-fire, saying it had been mediated by the United States, although only Pakistan quickly acknowledged an American role.

India and Pakistan’s latest military conflict has expanded, days after India carried out airstrikes in Pakistan that followed an attack by gunmen on tourists in India-controlled Kashmir last month