After years of court battles and political debate, the US military formally ended its ban on openly gay troops on Tuesday with little fanfare. The historic change would enter into force one minute after midnight (0401 GMT) Tuesday, Pentagon press secretary George Little told reporters. \"We are prepared for repeal. It will occur at 12:01 tomorrow,\" Little said. Defense Secretary Leon Panetta and the chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, will hold a news conference to coincide with the repeal but the Pentagon was taking a business-as-usual approach with no high-profile ceremonies or events planned, officials said. After Congress voted in December to lift the ban, the military reviewed its policies and had 2.25 million service members -- virtually the entire force -- undergo training to ensure a smooth transition, according to Little. The 1993 law that will expire, known as \"Don\'t Ask, Don\'t Tell,\" required gay and lesbian troops to keep quiet about their sexual orientation or face expulsion from the force. Roughly 14,000 service members have been kicked out of the military under the rule. Former president Bill Clinton backed lifting the ban altogether but after he met with strong opposition from commanders and lawmakers, he accepted the \"Don\'t Ask, Don\'t Tell\" compromise. The military already has begun accepting applications from gay or lesbian recruits but said it would not take any action on them until Tuesday when the prohibition officially ends. Gay rights groups, including soldiers who were discharged under the rule, are holding celebrations across the country on Tuesday to mark the change.   Zeke Stokes, spokesman for Servicemembers Legal Defense Network, said the change in the military\'s policy could help secure the eventual legalization of same-sex marriage. \"In the United States and perhaps around the world, the military tends to be one of the more conservative institutions in society,\" Stokes told AFP. \"For the military to embrace this, for the American people to see the military embrace this, make it work, see it work. I think it makes a difference in other civil rights issues. \"In every country where same-sex marriage is legal, open military service preceded it,\" he said. Before Congress voted in December to repeal the ban, the military carried out a survey and found that most troops did not believe that allowing openly gay soldiers to serve would cause any major disruption. Out of all the services, opposition ran stronger among the Marine Corps. One marine working in the White House, however, backed the change. According to GQ magazine, the marine recounted how he approached President Barack Obama when no other aides were present and thanked him for working to end the ban. \"You know, sir, I want to let you know that there are a number of us that work very close to you who appreciate very much what you\'re doing on \'Don\'t Ask, Don\'t Tell\' more than you probably realize,\" he told the president.