The operator of Japan's post offices has conducted the first trial in the country of the most difficult level of drone flight.

The drone took off from a post office in the town of Okutama in Tokyo with a package weighing one kilogram. It took about five minutes to reach a house two kilometers away. It landed near the house, where the resident accepted the parcel.

It was what is called a "level-4" flight, because the drone leaves the operator's line of vision over a populated area.

In December, the government established national qualifications and certification for drone operators.

Japan Post Senior Executive Officer Koike Shinya said that people may feel suspicious when they see unfamiliar objects flying in the sky. He added that the company need the understanding of municipalities and their residents.

Japan Post plans to use drones for deliveries to areas difficult to reach over land. It hopes to alleviate labor shortages and reduce costs.

Drones are also being tested by e-commerce giant Rakuten Group and delivery firm Sagawa Express.