Justified & Stripped, the summer co-headlining tour featuring Justin Timberlake [ tickets ] and Christina Aguilera [ tickets ], is on hold indefinitely in the wake of the collapse Saturday (8/9) of a ceiling grid at Boardwalk Hall in Atlantic City, NJ.

According to The Press of Atlantic City, the cause of the collapse--which took place while the production was under construction at about 12:45 p.m. and caused three minor injuries to stagehands--is under investigation. Neither Aguilera nor Timberlake were in the building at the time.

The incident is estimated to have caused more than a million dollars in damage to the Justified & Stripped tour's lighting, sound, video and staging, according to a press release issued by Timberlake's camp, which added that it isn't known when the tour will resume.

"All attempts are being made to finish the tour and revisit postponed dates," the press release said. "Ticket holders for the postponed show are encouraged to hold on to their tickets, as they will be honored in the future."

According to Aguilera's official website, the tour's stops in Atlantic City; Albany, NY (8/11); E. Rutherford, NJ (8/13); and Hartford, CT (8/14) have been canceled. The status of the tour's remaining dates, which run from Aug. 16 through Aug. 24, wasn't known at press time.