El Paso , Texas -LRB- CNN -RRB- -- A brigade of U.S. troops originally scheduled to be among the very last to leave Iraq is being pulled out of the country months ahead of its planned departure , military officials said Saturday . The announcement follows news this month that a deal to keep American troops in Iraq past a December 31 , 2011 , deadline to withdraw was on shaky ground after Iraqi leadership said any remaining U.S. forces would not be granted immunity from Iraqi prosecution . Secretary of Defense Leon Panetta and other top brass have repeatedly said any deal to keep U.S. troops in Iraq beyond the withdrawal deadline must require a guarantee of legal protection for American soldiers . The Fourth Brigade Combat Team , First Armored Division , based at Fort Bliss , deployed to Iraq in August to replace two withdrawing brigades . The troops were sent with the understanding they would be among the last to leave the country and were told to expect up to a 12-month deployment , though it was n't clear how long they would stay in Iraq . But brigade officials informed hundreds of military families gathered Saturday at its headquarters that their troops would begin returning home within weeks . When family members inquired why soldiers were returning early , they were told by a military official : `` Basically , what 's happened ... is that the United States and Iraq have not come to an agreement , '' according to a CNN reporter who attended the meeting . Additionally , the brigade official told families : `` We were over there for a couple of missions . Those missions are finished . '' A U.S. military official in Iraq , speaking on condition of anonymity , confirmed to CNN Saturday the early withdrawal of this brigade , citing a number of possible reasons , including the lack of a deal on the legal immunity issue and the fact that the State Department is `` standing up '' its operations faster than expected . When the United States and Iraq agreed in 2008 to a withdrawal deadline , the two countries also signed off on a Strategic Framework Agreement that calls for a long-term bilateral relationship . As part of that agreement , the State Department is deploying thousands of workers to Iraq to take over where military officials leave off in their dealings with the Iraqi government . U.S. officials in Washington on Saturday declined to comment on reports that troops were being withdrawn ahead of schedule or because of a breakdown in negotiations , except to say the United States is committed to withdrawing all troops by the December 31 deadline . `` At the same time we 're building a comprehensive partnership with Iraq under the Strategic Framework Agreement including a robust security relationship , and discussions with the Iraqis about the nature of that relationship are ongoing , '' said Tommy Vietor of the National Security Council . Pentagon spokesman George Little also dismissed reports of a breakdown in talks with Iraqis , saying `` Suggestions that a final decision has been reached about our training relationship with the Iraqi government are wrong . Those discussions are ongoing . '' Officials at Fort Bliss said the brigade 's return is in line with the U.S. planned departure . `` In the process , we are bringing troops back home to meet the December 31st agreed-upon deadline , '' said Lt. Col. Dennis Swanson , a public affairs officer for the First Armored Division . When asked about the legal immunity issue , Major Gen. Dana J. H. Pittard , commander at Fort Bliss , said , `` We 're going to do what 's right by our soldiers . '' `` We should n't see American soldiers in Iraqi courts on trumped-up charges , '' he said . His comments echo recent statements by Panetta and U.S. Army Chief of Staff Raymond Odierno . Panetta said last week that negotiations over the legal immunity issue are ongoing between Iraq 's political leadership , U.S. Ambassador James F. Jeffrey and Gen. Lloyd J. Austin III , commander of U.S. forces in Iraq . The meetings include discussions about the rights of American troops and what will be required in order for those troops to assist Iraqi forces in the future , according to Panetta . `` If you 're going to play a large role in dealing with another country where it requires , as I said , a large group of troops to be on the ground and to be dealing with that country , I want to make damn sure that you 're protected , '' Panetta told sailors last Friday during a visit to Naples , Italy , home of the U.S. 6th Fleet . U.S. officials have been pressuring Iraq 's leadership for months for an answer to whether it would request a troop extension , with former Chairman of the Joint Chiefs of Staff Adm. Mike Mullen saying over the summer that the U.S. needed a a decision by August . The negotiations have been strained following WikiLeaks ' release of a diplomatic cable that alleged Iraqi civilians , including children , were killed in a 2006 raid by American troops rather than in an airstrike as initially reported by the U.S. military . The Pentagon dismissed the cable from U.N. investigator Philip Alston to U.S. officials , saying it had investigated the claims and found there was no merit . Shortly after the WikiLeaks cable gained attention in news reports in September by McClatchy Newspapers , Iraqi Prime Minister Nuri al-Maliki ordered an investigation into the deaths outside of Tikrit . U.S. officials have long said they believe Iraq may need help with training , counterterrorism , air defense , command and control and intelligence operations . Any U.S. troops remaining to do those jobs might also need additional security forces . The prospect of U.S. troops staying beyond the end of the year sits uncomfortably with many Iraqis , who have routinely questioned American motives following the 2003 U.S.-led invasion that toppled Saddam Hussein . Radical anti-American cleric Muqtada al-Sadr , whose Sadrist political party is closely aligned with al-Maliki , has vowed to escalate armed resistance if the U.S. military does not leave as scheduled , a move that could destabilize the country should his militia repeat the bloody battles it waged against American and Iraqi forces during the height of violence . Odierno said last month that there would be risks in leaving a large force of U.S. troops in Iraq , noting such a force could provoke new claims of U.S. occupation and distract from efforts to develop the Iraqi military 's abilities . He would not comment directly on reports that the White House administration had decided to leave between 3,000 and 5,000 troops , should they be requested by Iraq . Odierno , who served as the top U.S. commander in Iraq , said that training of Iraqi security forces was not complete . `` We need to probably be there to assist them at certain levels for a while , '' he said last month in a question-and-answer session with journalists at the Pentagon . As of last week , 41,000 U.S. military personnel remained in the country , according to Major Gen. Jeffrey Buchanan , spokesman for U.S. Forces-Iraq . Buchanan said Wednesday that `` we are on track , and we will meet our requirement to redeploy the last remaining military personnel from 41,000 down to zero by the end of the year . '' A brigade typically consists of between 3,000 and 5,000 soldiers . CNN 's Dan Lothian and Adam Levine contributed to this report .