If North Charleston’s nearly $3.2 million purchase of the former Shipwatch Square shopping center was a gamble, then the city is doubling down with its $2 million purchase of the vacant Charleston Naval Hospital across the street.

Together, the two properties represent a large bet that the city can guide a 40-acre redevelopment of the area around Rivers and McMillan avenues.

City officials said Tuesday that the federal government has agreed to accept the city’s revised offer for the 10-story vacant hospital on 24 acres, located across Rivers Avenue from the 16-acre Shipwatch Square site.

The U.S. General Services Administration had rejected the city’s offer of nearly $1.95 million in an online auction, but later agreed on $2 million.

With Shipwatch Square and the hospital property, Mayor Keith Summey’s administration is looking for private developers to step in with plans the city would approve — a major grocery store to anchor Shipwatch Square, for example.

Summey has said he has no particular plan for the hospital site, but wants the city to have control over what happens there. The purchase will be made with money from the city’s $19 million fund balance, spokesman Ryan Johnson said.

Johnson said he didn’t know if the city would move quickly to market the site or seek requests for proposals.

“We are still weighing our options and once we close on the property, we should have a plan developed to move forward,” he said.

The city’s $2 million offer for the hospital site came after City Council on Thursday authorized the administration to raise the city’s bid slightly. One member of council, Ed Astle, opposed a higher offer and worried that the city would be purchasing “a money pit.”

According to Summey, the federal government has been paying $1.2 million yearly for security guards, heating and cooling for the hospital, which was shut down two years ago. Astle worried about the city taking on those expenses.

Councilman Bobby Jameson said Tuesday the hospital site represents “a special opportunity” for the city, if handled correctly.

“If we accept professional responsibility we can create capital assets for our citizens, something few cities get the opportunity to accomplish,” he said. “North Charleston is growing, we are financially doing well in this down economy, and this could be another benchmark in that positive movement.”