LAS VEGAS — Hillary Clinton on Thursday pledged to repeal an immigration provision that blocks undocumented immigrant from returning to the United States legally for a wait period of either three or ten years.

The provision, which was included in the 1996 Illegal Immigration Reform and Immigrant Responsibility Act, prevented undocumented immigrants who had overstayed their visas or crossed the border illegally from returning to the U.S. legally after an extended wait period, depending on the length of time that they had been in the country illegally.

Clinton’s pledge came in response to a question at the MSNBC/Telemundo town hall in Las Vegas Nevada that was actually asked of Vermont Sen. Bernie Sanders. A woman in the audience said that while she and her children were legal immigrants, her husband was not and had voluntarily left the country seeking to normalize his status. According to the 1996 provision, he was ordered to remain in Mexico for 10 years before he could be reunited with his family in the United States.

“I want to tell you, I will end the three and ten-year bar provision so that you do not have to ever face that again,” Clinton said pointing the woman out in the audience after Sanders had left the stage.

Sanders, when faced with the same question from the woman earlier in the event, responded that he would work with Congress to address the issue.

“My own view is that our policy as a nation and what I believe is, you should unite families not divide families,” Sanders said. “You should not be sending people back to a country that you can barely remember.”

Undoing the provision would require an act of Congress, Clinton acknowledged.

“It does have to be done legislatively,” Clinton said. “I would do it on a separate piece of legislation and in comprehensive immigration reform.”

And she reiterated her pledge to address immigration reform as one of her top legislative priorities within her first 100 days in office. Clinton first made the comments in an October interview with Telemundo in which she said that in her first 100 days in office she would “work with both Republicans and Democrats to get a comprehensive immigration reform bill introduced as quickly as possible.”

On Thursday, she added: “If I’m fortunate enough to get the Democratic nomination, I will immediately begin working on the priority legislation that I want the Congress deal with right away, and immigration reform will be among those issues.”

During the event, however, Sanders tweeted that the three and 10-year bans were immigration provisions signed into law by former president Bill Clinton.

“Glad to hear @HillaryClinton’s promise to remove the three and ten year bars against returning immigrants put in place by the Clinton admim,” the his account tweeted.

Hillary Clinton responded by noting that Sanders joined a majority of Democrats and Republicans in Congress by voting for the bill.