Kansas City, Mo. ? A Chicago-area developer announced Thursday it would buy most of the Richards-Gebaur Memorial Airport land, moving the former Air Force base closer to becoming the international trade center that city officials long have envisioned.

CenterPoint Properties Trust said it would pay $5.6 million for the majority of the south Kansas City site and invest another $200 million to $300 million to transform it into a cargo hub.

“It really is the first step in launching the redevelopment,” said Shani Tate Ross, a spokeswoman for the Port Authority of Kansas City, which manages the land for the city.

The Port Authority estimated the project would create more than 3,000 jobs.

The deal covers all but about 100 acres of the 1,400-acre property. Proceeds of the sale would go to the Federal Aviation Administration.