US President Barack Obama is expected to announce that he is ordering the closure of the Guantanamo Bay prison camp within a year.
He is also expected to order a ban on abusive interrogations and a review of military trials for terror suspects.
Mr Obama is also to meet his top national security advisers and Secretary of State Hillary Clinton.
The focus on national security follows moves on Wednesday aimed at improving government ethics and transparency.
The measures included curbs on lobbying and a pay freeze for senior White House staff. Federal employees will have to sign up to new ethics procedures.
Also on Wednesday, judges suspended several of the military trials of terror suspects at Guantanamo, at Mr Obama's request. One trial involved several men accused in the 11 September attacks in the US.
The draft executive order on the Guantanamo Bay detention centre in Cuba was circulated by the Obama administration on Wednesday.
"The detention facilities at Guantanamo for individuals covered by this order shall be closed as soon as practicable, and no later than one year from the date of this order," the draft read.
It says anyone still in detention when the prison is shut "shall be returned to their home country, released, transferred to a third country or transferred to another United States detention facility".
Speaking on condition of anonymity, a White House official said the order would be signed on Thursday.
Mr Obama has repeatedly promised to close the Guantanamo Bay prison, where some 250 inmates accused of having links to terrorism remain and 21 cases are pending.
The legal process for these prisoners has been widely criticised because the US military acts as jailer, judge and jury, the BBC's Jonathan Beale reports from Guantanamo.
However, closing the prison will not be easy, he says. Questions remain over where those charged will be tried and where those freed can be safely sent.
On Thursday, Mr Obama is also expected to issue separate executive orders to review the military trials and to ban abusive interrogation techniques such as waterboarding - a form of simulated drowning used by the CIA.
Middle East envoy
Mr Obama was also due to visit the state department with Vice-President Joe Biden, where new Secretary of State Hillary Clinton arrived on Thursday morning to applause and cheers from staff members. The Senate confirmed her in the role on Wednesday.
She said defence, diplomacy and development were the three pillars of US national security and that the state department was in charge of two of them.
Outlining her priorities, Mrs Clinton said it was a new era for America.
Hillary Clinton said a new era for America was beginning
"President Obama set the tone with his inaugural address, and the work of the Obama-Biden administration is committed to advancing America's national security, furthering America's interests, and respecting and exemplifying America's values around the world."
President Obama is expected to announce his choice of an envoy to the Middle East. Former Senator George Mitchell is widely tipped for the role.
The widely-respected Mr Mitchell chaired peace talks on Northern Ireland that led to the Good Friday peace accord. He later led an international commission on the Middle East conflict.
Six other cabinet members were also approved on Wednesday, including Janet Napolitano as homeland security secretary and Steven Chu as energy secretary.
Several other positions are still to be confirmed, including Timothy Geithner as treasury secretary. His appointment has been delayed by questions over his late payment of taxes earlier this decade.
If confirmed as expected, Mr Geithner would play a key role in shaping the economic recovery plan that is at the centrepiece of the president's domestic agenda.
Late on Wednesday, a panel in the House of Representatives gave its support to a $358bn government spending package, giving the first post-inaugural backing to the Democrats' economic plans.