She also called her recent use of the term "illegal immigrants" a mistake. She implied that her wording at a campaign event in New Hampshire earlier this month had been a slip of the tongue.
"That was a poor choice of words," Clinton said.
Democratic rival Martin O'Malley had pointed to the remark as evidence of duplicity, accusing Clinton of selectively using harsh or more inclusive terminology for undocumented immigrants depending on the audience.
"I’ve talked about undocumented immigrants hundreds of times and fought for years for comprehensive immigration reform. And I will continue to do so," Clinton said Tuesday. "We are a country built by immigrants and our diversity makes us stronger as a nation — it’s something to be proud of, celebrate, and defend," Clinton said.
Clinton has said she wants comprehensive immigration reform that would give a path to citizenship for the more than 11 million people living and working in the United States who have entered the country illegally.
"And, let's not forget, if you look at their policies, most of the other Republican candidates are just Trump without the pizazz or the hair," Clinton said during the Facebook exchange. "They don't support a real path to citizenship."
House Speaker Paul D. Ryan (R-Wis.) has ruled out another attempt at immigration legislation for the balance of President Obama's term. Democrats and Republicans blame one another for the failure of the most recent attempt at an overhaul.
“Look, I think it would be a ridiculous notion to try and work on an issue like this with a president we simply cannot trust on this issue,” Ryan said this month in an interview with CBS’s “Face the Nation.”
“He tried to go it alone, circumventing the legislative process with his executive orders, so that is not in the cards.”
Clinton also supports expanding Obama's executive actions protecting some classes of illegal immigrants from deportation.
During a campaign appearance Tuesday in Boulder, Colo., Clinton appeared to point again at Trump, who has taken the hardest line against Syrian refugees among the GOP field.
"I have heard all this loose inflammatory talk about refugees," she told the Colorado audience. "I don't think that does us any good at all," in defeating the Islamic State.
"We must be willing to continue to take refugees into our country," Clinton said.
Also Tuesday, Clinton collected the endorsement of the Laborers International Union of North America. It is the latest large union to back her over Democratic presidential rival Sen. Bernie Sanders (Vt.)
"LIUNA is eager to work with Secretary Clinton, as the next president of the United States, to help enact legislation and promote policies that provide long-term investment in America’s roads and bridges, and encourage a real all-of-the-above approach to energy development," union president Terry O’Sullivan said.