More than two dozen elected officials from Prince George’s County — most of them backers of Maryland Lt. Gov. Anthony G. Brown — signed onto a letter Monday accusing Democratic gubernatorial rival Douglas F. Gansler of making “demeaning” remarks about the county during a campaign stop over the weekend.

During an appearance Saturday marking the opening of a regional campaign office in Forestville, Gansler promised to do more to bolster economic development and improve education in the majority African-American county.

While his pledges were well-received by those in the room, some of the appeals were based on “outdated stereotypes” of Prince George’s and did not acknowledge progress that has already occurred, according to the letter.

It was signed by officials including House Minority Whip Steny H. Hoyer (D-Md.), Rep. Donna F. Edwards (D-Md.), state Senate President Thomas V. Mike Miller Jr. (D-Calvert) and Prince George’s County State’s Attorney Angela D. Alsobrooks (D).

Gansler supporters, including his running mate, Del. Jolene Ivey (D-Prince George’s), emphasized the criticism was coming from politicians who didn’t attend the event and who, for the most part, belong to the “Democratic establishment” that has rallied around Brown in a bitter primary.

“Don’t let 28 people who weren’t there and have a vested interest in the status quo drown out the voices of the more than 200 Prince Georgians who cheered their support,” Ivey said in a statement. “The Gansler/Ivey team will not tell the people of Prince George’s they should smile and be happy with less than everybody else. We will fight for them to be part of our state’s shared prosperity.”

Among the Gansler comments cited in the letter was his assessment Saturday of amenities available in Prince George’s. Gansler, a former Montgomery County state’s attorney, said that when he was growing up, “You couldn’t shop in a mall in Prince George’s or go to a restaurant with a table cloth in Prince George’s. You had to come to Montgomery County or Anne Arundel County. And it’s not that different now.”

The “open letter” said those words were “demeaning and nothing could be further from the truth. The only thing that has ever prevented Mr. Gansler from shopping or eating in our county is the out-of-touch stereotypes that he’s now perpetuating to try to win an election.”

Gansler said at another point Saturday that while progress has been made in the jurisdiction, “there’s still education redlining going on in Prince George’s County.”

The letter encouraged other officials to sign on, saying “it’s important for leaders like us to send a clear message that Prince George’s County, OUR County, will not be used as a punching bag to further Doug Gansler’s — or any other politician’s — political career and self-interest.” Brown is a former Prince George’s delegate and still lives in the county.

In an interview Monday, Seat Pleasant Mayor Eugene Grant (D), who introduced Gansler at Saturday’s event, said he was “somewhat shocked” when he saw the letter.

“I don’t recall anyone coming up to me and expressing any concerns with what the candidate said,” Grant said. “There was nothing negative that was said.”

Ivey characterized the office opening as “an extraordinary event dominated by an outpouring of public support for a team that believes the children of Prince George’s deserve No. 1 schools and our hard-working families have earned thriving economic development.”

Prince George’s County Council member Derrick L. Davis (D), who helped gather signatures for Monday’s letter, said there had been “a groundswell” of people concerned about Gansler’s remarks since Saturday, when they were reported by The Washington Post.

In an interview, Edwards said she found it odd that Gansler was “insulting the people he wants to represent. … I invite him to spend some quality time in the county I know.”

The June Democratic primary also includes Del. Heather R. Mizeur (D-Montgomery).