The truce came after several days of the countries’ most expansive fighting in decades. One Indian official said the country would “deal strongly” with any violations.

The sudden announcement of a U.S.-brokered ceasefire followed four days of steady escalation between India and Pakistan and mixed signals from Washington.

The ceasefire had been expected to bring a swift end to weeks of escalating clashes, including missile and drone strikes, triggered by the mass shooting of tourists last month that India blames on Pakistan,