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.

India and Pakistan agreed to a ceasefire on Saturday after U.S.-led diplomacy, but hours later India said that Pakistan had violated the truce.