FAIRFAX, Va. — In her first appearance on the campaign trail in support of former Secretary of State Hillary Clinton, first lady Michelle Obama was greeted with chants of "four more years," all the while bashing Donald Trump for his comments questioning where President Obama was born and talking up Clinton as the Democratic nominee.

Soon after she took the stage at George Mason University, Obama spoke about first family's impending departure from the White House, which was met with chants from supporters.

"My family is almost at the end of our time in the White House," Obama said before she was drowned out by groans from the crowd before they started up the "four more years" chant. Throughout the chants, the first lady kept saying "noooo."

"You have Barack and me working on your behalf for the rest of our lives," she said, calming the crowd before proceeding with her speech.

Her speech Friday mirrored the one she gave in support of Clinton at the Democratic National Convention in late July, when she spoke glowingly about the former secretary of state, touting her as a fighter and someone who doesn't back down from a challenge. On Friday, Obama continued the Clinton campaign's line of attack over Trump's birther comments the real estate mogul blamed supporters of the former secretary for bringing it up in the first place.

"Then, of course, there were those who questioned, and continue to question for the past eight years up to this very day, whether my husband was even born in this country," Obama told the crowd, who greeted the comment with jeers. "Well, during his time in office, I think Barack has answered those questions with the example he's set by going high when they go low."

"We need someone who is going to take this job seriously," Obama said soon after. "We need someone who is steady and measured because when you're making life or death, war and peace decisions, a president can't just pop off."

Obama went on to take multiple shots at Trump despite never mentioning his name once, arguing the president can't be "erratic and threatening," adding that a candidate cannot traffick in "prejudice, fears and lies" on the campaign trail because it will reveal what they will be as the Commander in Chief.

Her remarks came only hours after Trump tried to put the birther issue to bed once and for all, saying that the 44th president was born in the United States during a press conference. However, the crowd was dismayed by the continued talk about Obama's birthplace.

"That definitely turned me off," said Matt Borja, a freshman at George Mason and a supporter of Trump who turned out to hear the first lady speak. He explained that he was a supporter of Sen. Marco Rubio during the primary process, but came to support Trump after Rubio endorsed him.

"He's officially changed his stance, which I'm glad about. I was not a diehard Trump supporter," he continued.

The first lady's appearance came at the tail end of a disappointing week for the Clinton campaign, which saw her poll numbers dip and Trump make inroads nationally and in key battleground states. It was marked by Clinton's three-day absence from the campaign trail after a medical episode while attending a memorial event commemorating the 15th anniversary of the 9/11 terror atttacks, as well as her remark that half of Trump's supporters belong in a "basket of deplorables," leading her supporters to worry about a loss in November.

"I'm terrified she's going to lose in the fall," said Kiera Johnson, a freshman at George Mason and a Clinton supporter. "If she does, the alternative to her is just so much worse that it's terrifying thinking that somebody is unqualified and so hateful could win the presidency of our great nation."