Dozens of Pennsylvanians were geared to make history Monday evening by raising the pride flag for the first time over Reading City Hall. Yet minutes before the event was slated to begin, the city's mayor, Wally Scott, prohibited council members and city employees via text message from hanging the flag.

“People were disappointed at first, then they just became angry,” Ben Renkus, president of the Reading Pride Celebration, the group that planned the event, told NBC News. “The event was at 4:45 p.m. and many people had to leave work early to attend.”

#ReadingPa was set to raise a flag to celebrate #Pride but Mayor Wally Scott said no at the last minute pic.twitter.com/9EzRf460Ei — Jeremy Long (@jeremymlong) July 15, 2019

The flag ceremony coincided with Reading’s 13th annual LGBTQ Pride Celebration, which kicked off this past weekend. The pride flag was supposed to be flown until Sunday, the last day of the festivities.

Following Monday's last-minute cancellation, Renkus said the group marched to a nearby park where Scott was known to hang out after work, but the mayor wasn’t there. The group now plans to attend the next city council meeting, which is scheduled to be held Monday, with their rainbow flags in hand to express their fury.

“What was supposed to be a proud and historical moment in history today for the City of Reading, the LGBTQ+ community and our allies, turned into a show of blatant, unacceptable discrimination,” the LGBT Center of Greater Reading wrote Monday in a statement posted to its Facebook page. “To those who were on the street today in support; and to those who were with us in spirit, we are resilient; we will continue the fight for our rights.”

Scott contends that anti-LGBTQ discrimination was not behind his decision to cancel the flag-raising ceremony. He said his decision was based on his belief that the rainbow pride flag is a political symbol, and flying it would be against city policy.

“It’s the policy not to put up or endorse movements,” Scott told NBC News. “Numerous people have come into the office asking to put up flags, and we just don’t do it.”

Scott said he’s been asked to put up a Confederate flag and a flag commemorating National Pot Smokers Day, among others.

Renkus does not agree with Scott’s interpretation of the rainbow pride flag, however, and said the flag “represents and validates a specific group of people.”

The rainbow flag has been a universal symbol of LGBTQ pride, equality and inclusion since June 1978, when it made its debut at the San Francisco Gay Freedom Day Parade.

Renkus filed a formal complaint with the Human Relations Commission at Reading City Hall, alleging that Walker’s actions were discriminatory.

“The city has had LGBTQ protections in its ordinance since 2009, and we believe the mayor’s refusal to allow us to fly the flag goes against those protections,” Renkus said. “He’s also the first mayor in the Pride Celebration’s history to not attend any Pride events.”

Renkus is hoping for an apology and the ability to fly the pride flag, noting that flags of other countries and a POW/MIA flag have flown over City Hall in the past.

Donna Reed, a member of the Reading City Council, said the council followed protocol and said Scott showed no indication that he would cancel the original flag ceremony beforehand.

Scott, however, claimed he did not know about Monday's flag ceremony until the afternoon of the event and insisted "nothing was done maliciously by me."

"I have no objections with them holding the flag on the City Hall steps," he said. "I just didn’t want to hang it up.”

News of the incident made its way to the state level, with Pennsylvania Lt. Gov. John Fetterman calling on Scott to reconsider his decision. Fetterman also announced his plans to attend a pride event in Reading to show solidarity with the city's LGBTQ community.

Calling on Mayor Scott to reconsider. Looking forward to attending @ReadingPride to affirm our administration’s strong support for LGBTQIA+ community in PA.🏳️‍🌈🏳️‍🌈 https://t.co/CDADC9OgNt — John Fetterman (@JohnFetterman) July 16, 2019

Meanwhile, Mayor Andrew Kearney of neighboring West Reading helped plan an impromptu flag ceremony at West Reading Borough Hall for the deflated Reading group.

"The people of West Reading don’t discriminate,” Kearney said. "An elected official should accept all citizens.”

While the impromptu West Reading flag ceremony didn't include the flag actually hanging from the city's borough hall, Kearney said he's working on it.

Reed said she hopes "something good comes out of this" pride flag controversy in Reading.

“All of us wanted to see the flag go up," she said. "I hope this highlights that everyone’s civil rights need to be guaranteed.”

FOLLOW NBC OUT ON TWITTER, FACEBOOK & INSTAGRAM