Republican presidential candidate Marco Rubio participates in a roundtable discussion in Manchester, New Hampshire, Nov. 4, 2015. Getty Images

U.S. Sen. Marco Rubio of Florida, a candidate for the Republican Party's 2016 presidential nomination, hardened his opposition Wednesday to President Barack Obama’s controversial Deferred Action for Childhood Arrivals (DACA) program, which allows young undocumented immigrants who were brought to the United States as children to apply for temporary legal status in the country. After being criticized by GOP rival Donald Trump, Rubio committed to seeking the end of DACA, the Washington Post reported.

Rubio has steadily been climbing in the polls, making him a prime target for Trump. The billionaire criticized Rubio on Tuesday, saying that Rubio's position on immigration should disqualify him from being elected president. Rubio had said in April that DACA would have to be revoked at some point, but did not think the program could be immediately terminated when the next president takes office.

“It cannot be the permanent policy of the United States,” Rubio said in April. “But I’m not calling for it to be revoked tomorrow or this week or right away.”

In response to Trump’s criticism, Rubio changed his tune Wednesday. When questioned in Manchester, New Hampshire, about whether he has planned to keep DACA going, even if Congress does not pass immigration reform, Rubio said he would end DACA.

Presidential candidate Donald Trump speaks while Sen. Marco Rubio looks on during a Republican presidential debate, Oct. 28, 2015, in Boulder, Colorado. Getty Images

Obama unveiled DACA in 2012, and it has long been despised by many conservatives. While Rubio’s hardened opposition to the initiative could help him attract votes during the Republican primary elections, the position could be risky for next November's general election by possibly alienating Latinos and other minority groups, according to the Washington Post.

Trump had also slammed Rubio for his questionable use of a credit card issued by the Republican Party of Florida during his time as a young state representative. Rubio had occasionally used the card for personal purchases, but ultimately reimbursed the party. Trump ridiculed Rubio’s use of the party’s account, calling him, “a disaster with his credit cards,” the New York Times reported.

In response to Trump’s attacks on his spending history, Rubio defended the use of his card Wednesday, and said that he will soon release years-old credit records that have not previously been made public.