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Story highlights

Trump on Wednesday declined to say that he would accept the results of the election

Obama also used the opportunity while in Florida to weigh in on the close Senate race

(CNN) —  

President Barack Obama admonished Donald Trump Thursday, saying the Republican nominee’s claims that he might not accept the results of next month’s election are “not a joking matter.”

“I want everybody to pay attention here. This is dangerous,” Obama said at a Hillary for America event in Miami Gardens, Florida.

“Because when you try to sow the seeds of doubt in people’s mind about the legitimacy of our elections, that undermines our democracy. Then you are doing the work of our adversaries for them.”

Obama also encouraged the crowd of about 1,800 at Florida Memorial University to take advantage of Florida’s early voting, telling the audience in doing so they can reject what the President called Trump’s “dark, pessimistic fear-mongering.”

“Our democracy depends on people knowing that their vote matters. That those who occupy the seats of power were chosen by the people,” Obama said.

On Wednesday night’s debate Trump, answered, “I will look at it at the time,” when asked whether he would concede if he loses on November 8. “I will keep you in suspense.”

Trump also doubled down on Thursday in Ohio saying he will accept the results of next month’s election as long as wins.

Obama also used the opportunity while in Florida to weigh in on the close Senate race in Florida between Republican Sen. Marco Rubio and his Democratic challenger, Rep. Patrick Murphy.

“Even Marco Rubio says there’s no rigging of the vote,” Obama said, “Which I’d like to give credit for, except he’s refuting the dangerous, unprecedented claims of a candidate he says he’s still going to vote for!”

Earlier this week, Obama released a new ad for the Democrat in the Sunshine State, the same week it was announced the Democratic Senatorial Campaign Committee was puling money for ads for Murphy.