Construction was halted Tuesday on a new, state-funded charter high school being built on the Southwest Side for the state’s largest charter-school operator, the politically influential United Neighborhood Organization, after the project’s general contractor said UNO has fallen behind in its payments for the work.

The move came five days after Gov. Pat Quinn’s administration suspended funding to UNO following Chicago Sun-Times reports on insider deals that state officials say violated terms of a $98 million state grant.

Patrick Cermak, the president of general contractor Wight & Co. of Darien, cited unspecified past-due payments in a letter to subcontractors explaining why it was halting work on the new UNO Soccer Academy High School at 51st and St. Louis, which is being paid for out of the state grant.

“We are aware that there are outstanding funds due on the project, and Wight is discussing the status of these with UNO,” Cermak said in the letter. “Our hope is for a timely resolution that addresses the state requirements, accounts for businesses working on the project and recognizes the importance of an on-schedule school opening for the students.”

The new school, which UNO planned to open in August, is more than half-finished, according to Tracey Mendrek, a spokeswoman for the contractor.

UNO officials declined to comment Tuesday.

They have estimated the total cost of the new school at $27.1 million, including $2.6 million for a soccer field, according to newly released state records. Wight had billed nearly $6.5 million for work on the school as of Feb. 5, the records show.

The Illinois Department of Commerce and Economic Opportunity cut off payments to UNO last week after investigating Sun-Times reports that the organization has paid a total of $8.5 millions out of the state grant to two contractors owned by brothers of a former top UNO executive, Miguel d’Escoto. State officials said UNO should have notified them it was using compaies owned by d’Escoto’s family members on state-funded schools and that the organization had violated the grant’s conflict-of-interest requirements.