Businessman and reality TV star Donald Trump is under fire for mocking a New York Times reporter with a congenital joint condition during a campaign rally in South Carolina this week, drawing a scornful rebuke from the reporter and others who called Trump’s actions “despicable.” br br The incident occurred as Trump was defending his recent claim that he had witnessed thousands of Muslims cheering in New Jersey on Sept. 11, 2001, as the World Trade Center collapsed. The assertion has since been fact-checked and discredited by law enforcement and government officials who were in New Jersey in the days and weeks following the terrorist attacks. br br On stage Tuesday, Trump berated Times investigative reporter Serge Kovaleski for his recent recollection of an article he had written a few days after the attacks. Trump appeared to mock Kovaleski's physical condition; the reporter has arthrogryposis, which visibly limits flexibility in his arms. br br “Now, the poor guy — you've got to see this guy, ‘Ah, I don't know what I said! I don't remember!' " Trump said as he jerked his arms in front of his body. br br The gesture was all the more personal because Kovaleski covered Trump while reporting for the New York Daily News between 1987 and 1993, a tumultuous period for Trump in which he struggled through several financial setbacks. br br “The sad part about it is, it didn’t in the slightest bit jar or surprise me that Donald Trump would do something this low-rent, given his track record,” Kovaleski said. br br Trump campaign spokeswoman Hope Hicks declined to comment on the record about the incident. A campaign official speaking on background said Trump was "not aware of any condition and was not mocking his physical appearance in any way." br br In a phone interview Wednesday, Kovaleski said he's sure Trump remembers him — and his condition. br br In his speech Tuesday, Trump defended his recollection of the Muslim revelers by citing a 2001 article by Kovaleski, who worked for The Washington Post at the time, noting that  “authorities detained and questioned a number of people who were allegedly seen celebrating the attacks and holding tailgate-style parties on rooftops while they watched the devastation on the other side of the river.” br br Those allegations were never corroborated but have persisted in online rumors in the 14 years since the attacks. In an interview on CNN this week, Kovaleski said he did not recall “anyone saying there were thousands, or even hundreds, of people celebrating.” br br That was the comment Trump was mocking in his speech. According to the campaign official, Trump "was merely emphasizing the uncertainty of the verbalwritten statement provided by the reporter in regards to his article." br br This is not the first time Trump has been panned for apparently mocking a person’s physical disability. In a July interview with NBC news, Trump lashed out at columnists Jonah Goldberg and Charles Krauthammer. Krauthammer had called the candidate a "rodeo clown." br br “I get called by a guy that can’t buy a pair of pants, I get called names?” Trump said at the time. br br Krauthammer is paralyzed from the waist down. br br Kovaleski's friends and colleagues took to social media this week to defend him — and excoriate Trump. br br "@sergenyt is one of the best reporters— and best people— I know. This is despicable," ESPN reporter and author Don Van Natta Jr. wrote on Twitter. br br "The measure of men. Know this: Serge Kovaleski, aka @sergenyt, is a journalistic rock star and one great colleague," wrote Times reporter Dan Barry. br br The Times also issued a sharply worded statement Wednesday: “We think it's outrageous that he would ridicule the appearance of one of our reporters,” a spokesman for the Times said.