US Republican presidential candidate Mitt Romney would end an Obama administration policy allowing some young illegal immigrants to stay in the country and work, though anyone already granted a reprieve from possible deportation would not see that permission revoked.
Mr Romney's campaign on Wednesday sought to clarify his position on the issue.
Mr Obama announced in June that he would prevent deportation for some people brought to the United States illegally as children.
Mr Romney told The Denver Post on Monday that he would not deport those who received permission to stay under the new Obama policy.
The campaign said on Wednesday it wanted to make clear that while Mr Romney would honour the two-year permission granted under Mr Obama's tenure, a Romney administration would not grant such permission.
The Obama campaign has criticised Mr Romney as "extreme".