The bipartisan debt supercommittee has yet to announce its first meeting, but outside groups are already poised to begin putting pressure on the group when Congress returns from its August recess next week.

The Alliance for Retired Americans is holding a conference at the Washington Hilton Sept. 6-9 at which organizers expect 500 seniors, labor leaders, administration officials and members of Democratic leadership to rally against the inclusion of any entitlement cuts in a debt-reduction deal.

Their message to the 12 supercommittee members is one that congressional Democrats have made throughout the debt battle: “Don’t balance the budget on the backs of seniors.”

Among the members expected to address the conference are House Minority Leader Nancy Pelosi (D-Calif.); Sen. Bernie Sanders (I-Vt.); House Democratic Caucus Vice-Chairman Xavier Becerra (Calif.), who is also a supercommittee member; Democratic National Committee Chairwoman Debbie Wasserman Schultz (Fla.); and Rep. Raul Grijalva (D-Ariz.).

Also attending will be Health and Human Services Secretary Kathleen Sebelius; NAACP Washington bureau director and senior vice president for advocacy and policy Hilary Shelton; and AFL-CIO President Richard Trumka as well as other labor leaders.

The seniors will also lobby members on Capitol Hill on Sept. 8, the same day that President Obama is slated to deliver his jobs address to a joint session of Congress.

The conference comes as members of both parties on the supercommittee have held preliminary meetings but have not set a date for their first bipartisan gathering. The members have until Sept. 16 to hold their first meeting; Republicans held an in-person meeting on Tuesday, while Democrats held a conference call on Wednesday.

A House Democratic aide said Wednesday that the group’s Democratic members plan to hold their first in-person meeting one day next week.

The group is tasked with identifying before Thanksgiving $1.5 trillion in deficit savings over the next decade. If members aren’t able to reach an agreement, an across-the-board cut of $1.2 trillion will be enacted to both defense and domestic discretionary spending.

An earlier version of this story inaccurately reported the name of the Alliance for Retired Americans. The story has been corrected.