OKLAHOMA CITY (AP) – Construction work on the unfinished American Indian Cultural Center and Museum in Oklahoma City will be suspended on July 1 because officials have run out of money for the project, in which $91 million has already been invested, the project's executive director said Thursday.

But private donors, tribal organizations and other groups that have pledged $40 million in matching funds have agreed to maintain them until officials develop a plan to complete the project, Executive Director Blake Wade said. Organizers feared that the pledges might be withdrawn after the Oklahoma Legislature rejected a $40 million bond issue for the project last month.

“We're not quitting,” Wade said at the visitor center of the unfinished museum located east of downtown Oklahoma City at the junction of Interstates 35 and 40. “We're dedicated to getting that job done.”

Although construction has been suspended, the project's builder, Centennial Builders, will continue to provide building and grounds maintenance and site security on a month-to-month basis to protect the structure. Maintenance costs will be about $52,000 a month, Wade said.

The unfinished site is already surrounded by a security fence and gates that are locked after hours to guard the museum's entrances.

Wade said he was “terribly disappointed” that lawmakers did not approve a bond issue that, coupled with private matching funds, would have completed the structure. Final construction cost is estimated at $171 million. Wade said the projected completion date was December 2014.

Developers have said the museum and cultural center will be a world-class, Smithsonian-quality facility that will house collections from Oklahoma-based American Indian tribes, the National Museum of the American Indian in Washington and other tribal museums, and attract tourists from around the nation and the world.

But most of the museum's buildings are only about 50 percent complete, officials said. Visitors walk on bare concrete floors, and plywood covers walkways that lead to a massive earthen promontory designed to resemble historic American Indian mounds.

The more than 200-acre site also includes about 40 acres set aside for commercial development that could include a hotel and restaurants, officials said.

Before the Legislature adjourned on May 25, opponents of the bond issue said lawmakers had already issued $63.4 million in bonds for the project and that annual bond payments total $5.5 million. Another $40 million bond issue would increase the annual bond payments to $9 million.

The Research Institute for Economic Development, a pro-business group, supported the bond issue and estimated the cultural center and museum would generate $3.8 billion in economic activity in Oklahoma City and the state over the next 20 years. Wade said Gov. Mary Fallin has pledged to work with lawmakers to pass the bond issue in 2013.

“It's a state agency and should be funded by the state,” Wade said.

Wade indicated that he would continue to seek private donations in the hopes of resuming construction as soon as possible. The Legislature convenes again in February.

Sen.-elect Kyle Loveless, in whose district the museum is located, said he supports its completion.

“I'm still learning about it,” Loveless said.

Although disappointed by the delay, Wade pointed out it took 85 years to complete the Oklahoma Capitol by finishing its dome. The Capitol was built between 1914 and 1917, but its dome was not dedicated until 2002 as part of the state's centennial celebration that ended in 2007, Oklahoma's 100th year of statehood.

But Chris Pribil, project manager for Centennial Builders, said piecemeal funding of the museum project has caused the overall cost of the project to rise.

“It has a major impact,” Pribil said. “It substantially increases the project's cost.”