Police are planning to deploy unmanned aerial vehicles to take photographs of demonstrators participating in unauthorized protests.
The new machines are based on military models currently in use abroad but are adapted to meet local requirements, a National Police Agency official said. The high-tech machines will incorporate an image detector allowing officers to effectively ``see’’ the face of a person wearing a mask.

The two models being considered have wingspans of about a meter and can operate at night and in bad weather. They may be equipped with special lighting systems.

The cost of the initiative is expected to be about 100 million won ($106,800).

Authorities plan to carry out inspections of two contending machines in March.

The police said such a tool is ``invaluable,’’ as Korean courts are demanding clear evidence that suspects violated laws during protests.

The Los Angeles Police Department uses a Sky Seer to monitor crime. It has a built-in global positioning system and can stay airborne for 70 minutes, flying at 48 kilometers per hour. Each unit costs from $25,000 to $30,000.