More than 20 people died on Wednesday in a torrential spell of monsoon rain in Pakistan, where downpours have swept away entire villages over the last week, killing more than 400.

Buner, Pakistan — Pakistan issued a flood alert Wednesday for some southern districts, warning of torrential rains, as rescue teams continued searching for missing people in the country's northwest, where severe floods killed hundreds over the past week.

The domestic and international flight operations at Jinnah International Airport were also affected, The Dawn reported.

Pakistan declared a public holiday in Karachi as the financial capital braced for more rain on Wednesday, after the arrival of the annual monsoon season left at least seven people dead and caused widespread flooding,

Khyber Pakhtunkhwa government's MI-17 helicopter had taken off from Peshawar for Bajaur when contact was lost over Mohmand tribal district, according to initial reports.