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.

The ceasefire between India and Pakistan appears to be holding on Sunday despite mutual accusations of violations, as media reported signs including airspace reopening in Pakistan and the resumption of businesses in border areas,

New developments in the nuclear powers’ harrowing four-day conflict, along with entrenched religious nationalism on each side, could signal more frequent battles ahead.