LONDON — The NBA has formed a joint venture with Anschutz Entertainment Group to design and develop about 12 multipurpose arenas in major Chinese cities.

The project was announced today at the O2 Arena in London, where the New Jersey Nets and Miami Heat played a preseason game. AEG runs the O2, and the venture will be equally owned by the two parties.

NBA commissioner David Stern did not say when the plan would be starting, or where the buildings would be located.

"We weren't going to start construction in the next couple of weeks," Stern said at a joint news conference with AEG president and CEO Timothy J. Leiweke. "We anticipate that in a relatively short order we will have laid out a road map of a dozen buildings or so throughout China."

Leiweke said it could take decades to complete the project.

"We think of this over the next 20 years, not the next year or two," he said, adding some would be new arenas and others would be created by renovating existing facilities.

"You're going to see a combination," Leiweke said. "Most of them will be built and designed from the ground up."

Stern said he hoped the venture would not be affected by the global financial meltdown.

"In terms of finances, we will be making investment decisions on a building-by-building basis," the commissioner said, adding they did have some ideas about where to start building.

"We hope there's going to be a rapid determination made over a period of months which cities are the right ones for this venture," Stern said.

Stern has been looking to increase the league's marketability overseas for several years, and teams are touring Europe for the third straight preseason.

On Friday, Stern said the NBA was "an arena closer" to European expansion because of the O2 World in Berlin, which will host a preseason game between the New Orleans Hornets and the Washington Wizards on Tuesday.

The development of the same type of arenas in China is an indication Stern wants to see more NBA teams playing outside the United States and Canada.

Besides acting as a sports venue, the new facilities will offer other amenities.

"Where feasible, the arenas will be developed in conjunction with surrounding cultural and entertainment districts potentially comprised of restaurants, retail outlets, cinemas, hotels, residential areas, sports training facilities and smaller live entertainment venues," the NBA said in a statement.

Besides numerous restaurants and a movie theater, David Beckham's football academy is near the O2 Arena in London.

In China, the NBA has a huge fan base, and Houston Rockets center Yao Ming was one of the biggest stars of this year's Beijing Olympics.

"The NBA currently has relationships with 51 Chinese telecasters, including a partnership of more than 20 years with national broadcaster CCTV," the NBA says.