Four of the remaining five candidates for the Republican nomination for president met in Detroit Thursday night for the Fox GOP debate just two days after Super Tuesday contests returned strong wins for Donald Trump. The real estate mogul won seven states in a series of primaries and caucuses Tuesday, strengthening his bid for the nomination.

Retired neurosurgeon and Detroit native Ben Carson was absent from the debate Thursday. While Carson has not officially dropped out, he said he did not see a “path forward” in the race, following Tuesday's results in which he did not win a single state.

"Even though I will not be in my hometown of Detroit on Thursday, I remain deeply committed to my home nation, America," Carson wrote in an official statement, adding, "Along with millions of patriots who have supported my campaign for President, I remain committed to Saving America for Future Generations."

With Carson absent and a slew of campaign suspensions in the past month, Trump faced off against Texas Sen. Ted Cruz, Florida Sen. Marco Rubio and Ohio Gov. John Kasich in the Fox News showdown Thursday. The candidates swapped blows, looking to sink support for Trump ahead of a series of caucuses Sunday.

Trump responded to criticisms made by former Massachusetts Gov. Mitt Romney by calling the 2012 Republican presidential nominee a "failed candidate." The GOP front-runner said Romney "wants to be back in the game."

The business mogul also responded to a jab made by Rubio earlier in the week concerning the front-runner's "small hands," insinuating the candidate also had a small penis. "I guarantee you there's no problem, I guarantee you," Trump said.

Despite not winning a single state in Super Tuesday, Kasich said that he would be a viable candidate for the Republican nomination because he had focused on the issues throughout the campaign, arguing that he would get "crossover votes."

Rubio challenged Trump to respond to policy questions without resorting to attacks or deflections. “He doesn’t have answers and he’s asking us to make him the president of the United States,” the Florida senator said. 

 “For 40 years Donald Trump has been part of the corruption you’re angry about,” Cruz launched, accusing the real estate mogul of cronyism.

Trump addressed a leaked off-the-record interview with the New York Times in which he reportedly said he would be flexible on the issue of immigration. After at first making vague observations about the nature of off-the-record journalism, the front-runner repeated his promise to build a wall on the southern border of the U.S. and to have Mexico pay for it. "There's always give and take, there's always negotiation," he added.

"We absolutely have to be able to keep the brain power in this country," Trump later said, speaking favorably on the idea of keeping highly-skilled immigrants, such as Ivy League graduates, in the country to work.

Cruz continued to trade blows with the front-runner, urging Trump to release the tape of him speaking to the New York Times to lay rumors to rest.

Trump spoke in his insult-style of debating, calling Cruz "Lying Ted" and Rubio "Little Marco."

 As candidates fielded questions on their plans to fight the Islamic militant group known as the Islamic State group, Kasich said the U.S. needed to focus on potential developments in Libya, where the organization has made headway in recent weeks.