The Obama administration is delaying completion of reports examining U.S. detention and interrogation policy, officials said Monday, in a sign of the formidable issues it faces in grappling with how to handle terrorism suspects as it prepares to close the military prison at Guantanamo Bay. The work of a Justice Department-led task force, which had been scheduled to send a report on detention policy to President Obama on Tuesday, will be extended for six months, according to senior administration officials. A second task force examining interrogation policy will get a two-month extension to complete its work, which had also been due Tuesday. 'These are hard, complicated, consequential decisions,' one official said in a White House briefing in which four officials spoke to reporters on the condition that the officials not be named. 'What we are trying to do is to make sure that we make the right decisions. And so they are looked at, they are reviewed and re-reviewed. By teeing them up to the president, we want to make sure that we have looked at every single angle, because he will challenge us on these issues.' The officials said the administration remains committed to closing the prison in Cuba by January 2010, as Obama ordered, but the delays are an indication of the political and legal complexities of making good on the president's timeline. Some of the Guantanamo Bay detainees may be deemed too dangerous to release but also too difficult to prosecute in federal court or before a military commission. Officials said Monday that it is still unclear how many Guantanamo Bay prisoners might be placed in some system of prolonged detention, and how that system might be structured. But they said that Obama will seek congressional backing for any system and not unilaterally assert his authority to hold detainees indefinitely under the laws of war. Officials had previously said they were considering an executive order to establish a system of indefinite detention. 'There is no intent in the administration to rely on anything other than congressional authority,' said one senior administration official. He said any system of prolonged detention would include periodic follow-up reviews on whether a detainee continued to pose a threat to national security. A separate interagency task force is examining the cases of the 229 detainees who remain at Guantanamo Bay, and is on track to complete its work by October. Officials said more than half those cases have been reviewed, with recommendations to transfer more than 50 detainees home or to third countries, and to prosecute others. While the task force report focusing on detention policy has been delayed, officials released an interim report on Monday evening. It said the decision on where to prosecute detainees will be made by lawyers from the Justice Department's national security division, along with personnel from the Defense Department, including military prosecutors. Various factors will be considered, including the need to protect intelligence sources and methods, and 'evidentiary problems that might attend prosecution in the other jurisdiction,' according to the report. The report does not specify what kind of evidentiary problems might arise. Human rights groups argue that military commissions, even if restructured, offer a lower standard of justice because of the ability, in some circumstances, to allow in evidence obtained under duress. The six-month delay in deciding on detention policy, coupled with the need to craft and pass legislation, suggests that the closing of Guantanamo Bay will come down to the wire. In separate interviews, some administration officials have said they fear the closing date could slide. One official said that, in its efforts to resettle detainees, the government is making 'good progress with a number of European countries and countries outside of Europe.' He cited, in particular, the Pacific island of Palau, which has offered to settle Chinese Uighurs held at Guantanamo Bay who have been ordered released by the courts. Four Uighurs have been resettled in Bermuda. The official said some countries are willing to help the administration even though Congress has barred the administration from resettling any detainees in the United States. 'If there are constraints, that's the terrain we have to deal with, and we will,' one official said. 