Republican mayoral candidate Scott Stone on Wednesday continued to press Democratic convention officials and Mayor Anthony Foxx over the number of convention jobs going to unionized labor.

Specifically, he questioned so-called project labor agreements that will require contractors to use union labor "to the maximum extent feasible."

Convention officials Tuesday awarded $7 million worth of contracts to temporarily renovate Time Warner Cable Arena and outfit the Charlotte Convention Center as a media workspace.

Convention CEO Steve Kerrigan said Tuesday that the contracts would maximize union labor while still providing jobs to local workers. He said there are no quotas on union participation.

"Steve Kerrigan continues to say they're going to maximize union labor," Stone told a handful of reporters outside convention headquarters. "If they're going to do that, how can they also use local labor when we don't have a lot of unions here?"

North Carolina, a right-to-work state, has the lowest percentage of unionized workers in the nation, according to the U.S. Department of Labor. Only 3.2 percent of North Carolina workers belong to unions.

Two of the three contracts awarded Tuesday went to partnerships between national and local firms. Charlotte-based Rodgers Builders won the construction management contract with two out-of-state firms.

Charlotte's Neighboring Concepts and an out-of-state partner were chosen as event architects.

"We have repeatedly stated that our intention is to maximize business opportunities for local companies," Dan Murrey, executive director of the convention host committee, said in a statement.

"We made good on that promise yesterday when we announced the firms that won the bid for construction manager and event architect, and we will continue to promote the use of local firms and local workers to carry out convention business."

Stone wrote Murrey and Foxx asking them to release copies of any labor agreements. He tried to personally deliver it to Murrey but could not get past building security.

Pat Rodgers of Rodgers Builders could not be reached. Darrel Williams of Neighboring Concepts declined to comment.

Foxx said he has tried to maximize local participation in the convention.

"If Mr. Stone does not want the convention to come to Charlotte, he should just say so," Foxx said in a statement. "It's no secret that the national parties have disagreements about labor. That's a partisan issue. What's not partisan to Charlotteans of all political stripes is that the convention presents a once-in-a-lifetime economic opportunity."

The issue of union labor is a sensitive one for Charlotte-area contractors.

Earlier this month, representatives of Carolinas AGC (Associated General Contractors) visited Foxx to discuss a number of issues, including the possibility of using union labor on construction projects, AGC spokesman Dave Simpson said.

"Using project labor agreements and possibly using union construction companies cause concerns," he said, "because North Carolina has a history of being a pro-employee, non-union state."