U.S. President Donald Trump on Friday threatened unspecified action against any protesters at his weekend re-election rally in Tulsa, Oklahoma, in a warning that his campaign said was not directed at peaceful demonstrators.

"Any protesters, anarchists, agitators, looters or lowlifes who are going to Oklahoma please understand, you will not be treated like you have been in New York, Seattle, or Minneapolis. It will be a much different scene!" Trump wrote on Twitter.

Marc Lotter, a spokesman for Trump's campaign, said Trump was referring to agitators and not peaceful protesters.

"The president supports peaceful protests and people who are exercising their First Amendment rights," Lotter told MSNBC in an interview following the tweet.

"If we see what we've seen in other cities with rioting, looting, setting buildings on fire and physical violence, then that's going to be something that's going to be met by police."

White House spokeswoman Kayleigh McEnany told reporters at a briefing that earlier destructive protests were unacceptable while peaceful demonstrators would be allowed.

"What he was meaning are violent protesters, anarchists, looters – the kind of lawlessness we saw before," she said.

The rally is Trump's first major re-election event following the novel coronavirus pandemic that shuttered much of the country and comes amid weeks of civil unrest over the treatment of African Americans and growing protests over racism and policing.

With more than 100,000 people expected in the area of the rally on Saturday, Tulsa mayor G.T. Bynum on Friday rescinded a curfew he had ordered for several downtown city blocks around the venue.

"Today, the Secret Service asked the City to lift the curfew order this weekend. In compliance with this request, the City has rescinded the order," the city of Tulsa said in a press release quoted by CBS News.

Bynum on Thursday had announced the curfew in an executive order and said it would only affect the area near the BOK Center, where Trump is to speak. Trump thanked Bynum in a tweet for canceling the curfew.

The order said the mayor had received information from law enforcement agencies showing "individuals from organized groups who have been involved in destructive and violent behavior in other states are planning to travel to the City of Tulsa for purpose of causing unrest in and around the rally."

The rally was previously scheduled to take place on Friday, Juneteenth day which commemorates the end of slavery in the United States.

Trump rescheduled the event to Saturday after public pushback, as Tulsa was home to one of the worst incidents of racial violence in the nation's history, where dozens of African Americans were massacred 99 years ago.

The Republican president faced backlash over a tweet he sent during the protests of George Floyd, a black man who was killed by Minneapolis police while in custody. "When the looting starts, the shooting starts," Trump wrote. The phrase evoked a white segregationist who was mayor of Miami in the 1960s, though Trump later said he was unaware of its origins.

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The Rev. Al Sharpton, a veteran civil rights activist set to address a Juneteenth event in Tulsa later on Friday, called Trump's tweet "disrespectful," especially following the recent deaths of Floyd and Rayshard Brooks, another African American man killed by police in Atlanta.

"To have a threat like that you're provoking an incident, and you're provoking an interaction that is unnecessary," Sharpton told MSNBC. 

Trump's Tulsa rally will also come amid the coronavirus pandemic, which has infected about 2.2 million people and taken nearly 120,000 lives in the United States.

Health experts have warned against large-scale gatherings, as some states, including Oklahoma, are seeing a surge in confirmed cases as they reopen.

(With input from Xinhua, Reuters)