A government official said Mr. Obama’s order on the C.I.A. would still allow its officers abroad to temporarily detain terrorism suspects and transfer them to other agencies, but would no longer allow the agency to carry out long-term detentions.

Since the early days after the 2001 attacks, the intelligence agency’s role in detaining terrorism suspects has been significantly scaled back, as has the severity of interrogation methods the agency is permitted to use. The most controversial practice, the simulated drowning technique known as water-boarding, was used on three suspects but has not been used since 2003, C.I.A. officials said.

But at the urging of the Bush administration, Congress in 2006 authorized the agency to continue using harsher interrogation methods than those permitted for use by other agencies, including the military. Those exact methods remain classified. The order on Guantánamo says that the camp, which received its first hooded and chained detainees seven years ago this month, “shall be closed as soon as practicable, and no later than one year from the date of this order.”

The order calls for a cabinet-level panel to grapple with issues including where in the United States prisoners might be moved and what courts they could be tried in. It also provides for a new diplomatic effort to transfer some of the remaining men, including more than 60 that the Bush administration had cleared for release.

The order also directs an immediate assessment of the prison itself to ensure that the men are held in conditions that meet the humanitarian requirements of the Geneva Convention. That provision appeared to be a pointed embrace of the international treaties that the Bush administration often argued did not apply to detainees captured in the war against terrorism.

The seven years of the detention camp have included four suicides, hunger strikes by scores of detainees, and accusations of extensive use of solitary confinement and abusive interrogations, which the Department of Defense has long denied. Last week a senior Pentagon official said she had concluded that interrogators at Guantánamo had tortured one detainee, who officials have said was a would-be “20th hijacker” in the attacks of Sept. 11, 2001.

The report of Thursday’s announcement came after the new administration late Tuesday night ordered an immediate halt to the military commission proceedings for prosecuting detainees at Guantánamo and filed a request in Federal District Court in Washington to stay habeas corpus proceedings there. Government lawyers described both delays as necessary for the administration to make a broad assessment of detention policy.