PORTLAND — Three southbound ramps to I-295 will be closed most nights for at least two weeks for construction work, the Maine Department of Transportation said this morning.

The closings start tonight for the southbound on and off ramps at exit 6A (Forest Avenue) and the southbound on-ramp from the Fore River Parkway. Detour routes will be marked for drivers, MDOT said.

The ramps will be closed from 7 p.m. to 6 a.m. tonight and Friday night, and then Sundays through Thursdays for at least two weeks, the department said. The duration of the closings depends on the pace of the construction and the weather, MDOT said.

Workers will be repairing and replacing pavement on the Forest Avenue and Fore RIver Parkway overpasses, part of a substantial repair and improvment project on 295 that will take place into the fall.