NEW YORK - Huma Abedin, the top aide to Democratic Presidential candidates, joined Twitter Monday and used her first-ever tweet to denounce Republican presidential candidate Ben Carson for saying a Muslim should not be president.

Carson is under fire for his Sunday comment on NBC's news programme "Meet the Press" that he "would not advocate that we put a Muslim in charge of this nation." Abedin, a Michigan-born Muslim-American raised in Saudi Arabia by a Pakistani mother and an Indian father, tweeted: "You can be a proud American, a proud Muslim, and proudly serve this great country. Pride versus prejudice."

Nick Merrill, Clinton's traveling press secretary, also tweeted out a behind-the-scenes video of Abedin's first tweet. "This is too good not to share. @HumaAbedin pressing send for the first time," he said. Mitt Romney, the 2012 Republican presidential nominee, also took to Twitter on Monday to swipe at Carson."Of course, no religious test for the presidency -- every faith adds to our national character," tweeted Romney, who is Mormon.

Abedin is among Clinton's closest staffers and vice-chairwoman of her campaign. She travels with the Democratic front-runner to campaign events -- as she did during Clinton's first run, in 2008. She was Clinton's deputy chief of staff at the State Department.

The wife of former Democratic Congressman Anthony Weiner, Abedin is also a controversial figure among conservatives. Five Republican congressmen in 2012 claimed that Abedin has three family members connected to the Muslim Brotherhood -- a claim that was rejected by others, including Arizona Republican Senator John McCain. Senate Judiciary Committee Chairman Chuck Grassley has also raised ethical questions about Abedin's pay at the State Department, alleging that she held other jobs at the time.