Pakistan has issued a flood alert for some southern districts, warning of torrential rains, as rescue teams continued searching for missing people in the northwest, where severe floods have killed hun

Anguished Pakistanis searched remote areas for bodies swept away by weekend flash floods as the death toll reached 277 on Monday.

Across Pakistan, monsoon rains that began in late June have been heavier than usual, killing at least 645 people. Four hundred of those deaths were in the northwest alone, where narrow valleys and river-carved gorges funnel rainwater into sudden torrents.