Real-estate mogul Donald Trump said on Monday that the hecklers who interrupt his rallies remind him a bit of former US Secretary of State Hillary Clinton.

At a campaign rally in Massachusetts, the Republican presidential front-runner said that the hecklers' weak voices reminded him of Clinton.

"They remind me a little bit of Hillary. No energy, no stamina, no strength," Trump said.

He has frequently accused Clinton of having "no stamina," which some observers have interpreted as a jab at her age and health. Trump is actually just over a year older than Clinton, though both candidates have released health summaries affirming their fitness for the Oval Office.

Trump was repeatedly interrupted by hecklers during his Monday event in Lowell, Massachusetts, in which over six different groups shouted during his speech.

His campaign has become accustomed to a high number of protesters during rallies, and has even developed a routine for how to handle disruptions. Trump will lead the crowd in chants of "U-S-A," wave at protesters as they exit, and occasionally tell security to "get them out of here" as his audience roars in approval.

At Monday's rally, Trump also compared his own response to hecklers to how US Sen. Bernie Sanders (I-Vermont), a Democratic presidential candidate, handled Black Lives Matter protesters last summer.

"I remember Bernie Sanders, when they took over his microphone," Trump said. "That's not happening with Trump, folks. Wasn't that a pathetic scene?"

Clinton takes a much different tack with people who interrupt her campaign events.

If the disruption isn't incredibly notable, the Democratic front-runner will often attempt to power through or wait until the heckler is escorted out. At a December event in front of immigrant advocates in New York, Clinton was interrupted twice by protesters speaking out against one of the corporations sponsoring the event, but she did not stop her speech.

But during a town-hall event on Sunday, Clinton did address a heckler who stood up to confront the former secretary of state about her husband's sex scandals.

"You are very rude, and I'm not ever going to call on you," she said.