U.S. President Barack Obama on Friday visited activists who are fasting in Washington to protest the slow pace of immigration reform in the Congress. Obama, accompanied by First Lady Michelle, visited a Fast For Families event in the National Mall, where immigration advocates are fasting to call attention to the push for reform. According to the White House, Obama thanked the fasters for their sacrifice and dedication, telling them the country is behind them on immigration reform. "The President told them that it is not a question of whether immigration reform will pass, but how soon," said a White House official. "He said that the only thing standing in the way is politics, and it is the commitment to change from advocates like these brave fasters that will help pressure the House to finally act." The immigration activists comprising Fast For Families have abstained from all food except water since Nov. 12, and are calling for the Republican leadership in the House of Representatives to take up action on comprehensive immigration reform. The Republican-controlled House has refused to take up an immigration reform bill passed by the Senate in the summer, choosing to advance the issue in a piecemeal fashion. The White House said there were 18 day fasters present at Obama 's visit, and two activists who have been fasting for 18 days straight since Nov. 12. A host of administration officials have visited the fasters before Obama, including Vice President Joe Biden, Secretary of Agriculture Tom Vilsack, Secretary of Labor Tom Perez, White House Chief of Staff Denis McDonough, White House Director of the Domestic Policy Council Cecilia Munoz and Obama's Senior Advisor Valerie Jarrett.