A Pakistani security official was killed while four were injured on Monday when unidentified militants attacked a police van deployed to protect the population census team in the restive Khyber Pakhtunkhwa province, the second such attack in the province in less than a week.

The armed terrorists opened fire at a police mobile team on duty with the population census team in Tank district's Kot Azam area in the province, a police official said.

The militants managed to flee from the scene after the shootout, following which police sealed the area and launched a massive combing operation to nab them.

The injured police officials were admitted to a nearby health facility.

This is the second such attack on the census team in the province. On March 8, a Pakistani security official was killed and two others were injured when unidentified militants attacked a police van deployed to provide protection for the population census team in the Dera Ismail district of the province.

Pakistan on March 1 launched its first-ever digital population and housing census.

The country's Bureau of Statistics is conducting the census amid tight security.

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