BEIJING - Chinese scientists and engineers are designing drones to help firefighters rescue trapped people, especially in high-rise building fires.

Developed by China Academy of Launch Vehicle Technology (CALT), the drones can quickly fly into a building via doors or windows, search for trapped people and plan rescue routes.

When a fire occurs in a high-rise building, firefighters often have to walk upstairs and their sight is affected by heavy smoke, making it hard to plan a rescue route.

According to Xu Jian, designer at CALT, the drones can be quickly flown into the fire location to access the situation before firefighters arrive.

"For a skyscraper with a height of around 500 meters, it takes about half an hour for firefighters to climb the stairs to the top floor, but the drones take only two minutes," Xu said.

The drones can avoid obstacles, draw a three-dimensional map indicating the distribution of obstacles, and plan a barrier-free rescue route.

They are also equipped with cameras and pictures can be transmitted back to the ground in real time, which help firefighters locate trapped people.

The exterior of the drone is made of a composite material commonly used on rockets, allowing it to withstand a high-temperature environment of 200 degrees.

China has a huge demand for the drones and they are expected to be put into use by the end of this year, Xu said.