Michele Bachmann announced Wednesday that she is ending her bid for the Republican presidential nomination to challenge President Barack Obama after her terrible showing in the Iowa caucuses.

The conservative Minnesota congresswoman's decision, widely expected following her Iowa result, leaves her supporters up for grabs by the other candidates, particularly former Pennsylvania senator Rick Santorum, former House of Representatives speaker Newt Gingrich and Texas Gov. Rick Perry.

"I have decided to stand aside," Bachmann said at a hastily arranged news conference, hours after the caucus results showed her trailing all of her active opponents but Jon Huntsman, the former Utah governor who did not campaign in Iowa. "I will not be continuing in this race for the presidency."

Her campaign manager, Keith Nahigian, told The Associated Press that Bachmann has "no time frame or person" in mind for an endorsement of another candidate.

Bachmann said she had no regrets and will continue to fight for the causes she emphasized during the campaign, including to overturn Obama's "socialist policies."

It has been a long, deep slide for the congresswoman, who enjoyed a high point in her campaign when she won a Republican straw poll in Iowa in August. But her campaign steadily lost support since then, beginning with Perry's entry into the race on the day of her straw poll win.

References to 'Obamacare'

Bachmann, 55, had told a small group of supporters Tuesday night that she was staying in the race as the only true conservative who can defeat Obama.

In her statement, Bachmann referred repeatedly to "Obamacare" — the health care law Obama signed in 2010 — and said the Republican Party must not miss a "once-in-a-lifetime opportunity" to repeal it and the financial regulatory overhaul law known as Dodd-Frank.

Santorum's near-tie with Iowa caucus winner Mitt Romney topped a rise from deep in the polls to contender for the presidential nomination.

Republican presidential candidate Texas Gov. Rick Perry is greeted by supporters after speaking on caucus night on Tuesday in West Des Moines, Iowa. (Evan Vucci/Associated Press)

Like Bachmann, Perry took a blow in the caucuses — finishing fifth. He flew home to decide whether to stay in the race. It appears the answer is "yes." He tweeted Wednesday that he was bound for South Carolina.

Perry's camp said he would be at Saturday's Republican debate in New Hampshire, but he intends to focus on South Carolina's primary on Jan. 21.

Before Romney's Iowa victory was announced, the former Massachusetts governor added to his already formidable national network by announcing the endorsement of Sen. John McCain, who twice won the New Hampshire primary and was the Republican nominee in 2008.

Romney accepted the endorsement in a joint New Hampshire appearance Wednesday afternoon. New Hampshire will hold its primary on Tuesday.