Beijing Municipal Public Security Bureau signed a contract Thursday with Italian firm Agusta Westland to buy an AW139 helicopter.

The bureau will purchase two CA109s from the joint venture Agusta Ltd. Co. based in east China's Jiangxi Province. It will get another such helicopter for free, under the contract signed with the company.

The first-ever Beijing police aircraft is expected to arrive in April next year.

The helicopters would fly outside the Third Ring Road in accordance with the air administration rules of the Chinese capital, said Wang Bao, an official with Beijing Air Force Command.

The helicopters will help direct ground traffic, arrest criminal suspects, join anti-terrorist operations, support disaster-relief campaigns and deal with other emergency activities.

The take-off peak load for the AW139 is 6.4 tons. It is able to carry 15 people with a maximum speed of 318 km per hour.

While the CA109, already in use by police forces in the mainland cities of Shenzhen, Zhengzhou and Dalian, is able to carry six people at a top speed of 272 km per hour. Its maximum load is three tons taking off.

The CA109s, equipped with infrared detection systems, are able to transmit pictures taken in the air to the ground, representatives with the Jiangxi-based firm said.

Delegates would not discuss the cost or details of Beijing's air police squad.