BANGOR, Maine — U.S. Postal Service officials plan to look closer at concerns raised by members of the city planning board, which on Tuesday denied a site plan for improvements to a downtown building that the Postal Service wants to use as a post office.

Postal Service regional spokesman Tom Rizzo said Wednesday that all alternatives are being explored in the wake of Tuesday’s decision, but he declined to be more specific.

“We do need to move soon. We don’t have a choice on that,” he said. “But we’re committed to serving the residents of Bangor.”

Renovations of the Margaret Chase Smith Federal Building on Harlow Street, which has housed the Bangor post office since the 1960s, have forced Postal Service officials to look for a new home. They must be out of the federal building by May 1.

Last month, officials visited the city to tour a handful of potential sites, including the former 3rd District Court building, the former Miller’s Restaurant and temporary Hollywood Slots facility on Main Street, and empty space at the Bangor Daily News building, also on Main Street.

The Postal Service apparently settled on space at the District Court building at the corner of Hammond and Franklin streets, which is owned by Penobscot County and would be leased to the Postal Service.

Penobscot County submitted a site development plan to build a 22-foot-by-25-foot loading dock and reconfigure the parking at the downtown site to accommodate a retail post office. Planning board members, however, had concerns about parking and pedestrian safety associated with that site and decided not to support the plan.

City Planner Dave Gould said Tuesday that the site plan denial does not mean the post office couldn’t lease the space, but any site improvements would need planning board approval.

County Administrator Bill Collins said he and representatives from WBRC Architects-Engineers, which was contracted to make site improvements, would consider some of the planning board’s concerns and come up with a revised plan that addresses those concerns.

“Hopefully, we’ll be back before them again soon,” she said.

The next planning board meeting is scheduled for March 2.