Republican presidential nominee Donald Trump's campaign released a new ad Tuesday that focuses on opponent Hillary Clinton's health and recent bout with pneumonia.

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The ad, called "Dangerous," features images of masked gunmen and nuclear weapons as a sick Clinton stumbles toward a vehicle.

"Hillary Clinton doesn't have the fortitude, strength or stamina to lead in our world," the ad's narrator says.

Clinton's health has been questioned by opponents and on conspiracy websites. Her pneumonia diagnosis was revealed after she was seen stumbling while leaving a 9/11 memorial ceremony in New York. Following that incident, her doctor, Lisa Bardack, said Clinton had been treated for “mild, non-contagious bacterial pneumonia.”

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“She is recovering well with antibiotics and rest,” Bardack wrote last month. “She continues to remain healthy and fit to serve as president of the United States.”

The ad's release came the same day Trump tweeted that "the shackles have been taken off" and launched attacks against fellow Republicans, calling House Speaker Paul Ryan "weak and ineffective," Sen. John McCain "very foul-mouthed" and "disloyal" Republicans "far more difficult than Crooked Hillary."

– The Cox Media Group National Content Desk contributed to this report.