PORTLAND (AP) — Top leaders from FairPoint Communication and unions representing 1,700 striking workers in Maine, New Hampshire and Vermont are to gather in Washington, D.C., to resume negotiations.

The International Brotherhood of Electrical Workers and the Communication Workers of America are hoping for a breakthrough during the closed-door talks scheduled for Sunday.

It’s the first time the two sides have met since a fruitless a one-hour session Nov. 18 in Boston. This time, the federal mediation service plans to take an active role.

FairPoint said it’s willing to negotiate but doesn’t want to budge on the employees’ core issues: hiring contractors, changing pension plans and reducing health care benefits.

Workers are especially concerned about contract workers, fearing they’ll eventually be replaced by lower-paid, less-qualified contractors.

Workers have been on strike since October.