Tesla Motors has received a $3 billion building permit for construction of a battery assembly plant in Tucson.

The permit is for a one-story building of up to 5 million square feet in size at an address “to be determined.” It was issued by the city of Tucson development services department.

Tucson is one of several sites that Tesla is considering for a “gigafactory” to make batteries for its electric vehicles. The company has said the factory would employ about 6,500 people. Cities in California, Nevada, New Mexico and Texas also are finalists.

Mayor Jonathan Rothschild sent the permit and a brief memo to Tesla officials Wednesday.

“Attached is a City of Tucson permit, ready for your signature,” the memo reads. “Just letting you know the City of Tucson is ready to proceed as soon as you are.”

During a recent visit to Tucson, Tesla officials expressed concern that the project might get delayed due to permitting red tape, Roths-child said.

“This is a concrete sign that, not only can we act expeditiously, but we’re ready,” Rothschild said.

The mayor would not disclose how many site visits Tesla has made to Tucson.