Washington (CNN) -- Former House Speaker Newt Gingrich said Sunday he will release his income tax return this week, and he reiterated his challenge for Republican front-runner Mitt Romney to do the same.
Gingrich's comment on the NBC program "Meet the Press" continued his campaign to get Romney to disclose details of his personal wealth.
Romney, the former Massachusetts governor, has said he so far has complied with legal disclosure obligations, but added he might release his tax returns or further information in the future.
Gingrich said Romney will have to do it at some point if he is chosen by Republicans to take on President Barack Obama in November.
"Gov. Romney, if he plans to stay in the race, ought to plan to release his records," Gingrich said, adding that he plans to make public his tax return on Thursday, two days before the South Carolina primary.
Romney has won the first two contests of the Republican presidential nomination process in Iowa and New Hampshire. South Carolina will be the first primary in a Southern state, and Gingrich and other candidates are hoping the state's conservative political leanings will stop the momentum of the more moderate Romney.
Gingrich said Sunday it would be wise for Romney to release his tax return now, instead of having the issue come to a head in the fall amid a one-on-one campaign against Obama.
"The country deserves accountability and deserves transparency," Gingrich said. "These are big issues and not issues you can hide from."