The US Senate has voted to continue to allow Guantanamo inmates to be tried on US soil, removing a hurdle as the Obama administration seeks to close the camp, BBC reported.
The measure, which was passed by the House last week, permits Guantanamo detainees to be brought to the US only in order to face trial in US courts.
Those cleared cannot remain in the US. The bill - passed 79-19 by the Senate - largely mirrors existing restrictions.
It will now go to President Barack Obama to be signed into law.
Mr Obama has set a 22 January 2010 deadline for closing the Guantanamo Bay detention centre in Cuba, where more than 220 inmates are still held.
While some will be tried on US soil, others could be sent to abroad or face military tribunals.
The legislation passed by Congress on Tuesday removes one of the many legal, diplomatic and political obstacles to the closing of the Guantanamo detention centre.
This legislation represents the clearing of a potential roadblock for President Obama as he considers the vexed task of closing the Guantanamo Bay prison camp.
It is largely an extension of current policy, but given the fierce resistance in the US to letting Guantanamo inmates onto its soil for any reason, even preserving the status quo represents a small victory.
What this bill does not offer is any help on the question of what happens to those inmates once they have been through a judicial process.
The legislation does not allow those acquitted to stay in the US, and those convicted will not be able to serve their sentences in US prisons.
Under its terms, Congress must be provided with a detailed assessment of the security risk involved before a detainee can be brought to the US.
The administration must also give 15 days' notice of any transfer.
Some Republicans have objected to plans to hold Guantanamo detainees in US prisons, arguing that they do not deserve the protections afforded under US law.
"There is too much at stake to grant the unprecedented benefit of our legal system's complex procedural safeguards to foreign nationals who were captured outside the United States during a time of war," said Senator Saxby Chambliss during the debate.
Correspondents say the legislation will be considered a victory for President Obama.
Under its terms, those convicted will not be able to serve their sentences in US prisons, and those cleared will not be allowed to remain on US soil, even when no other country will accept them.
The matter is to be decided by future legislation or by the Supreme Court - which has begun hearing an appeal by a group of Chinese ethnic Uighurs, who were cleared while being held at Guantanamo.
Their lawyers argue that they should be allowed to resettle in the US rather than China, where as ethnic Muslim Uighurs they would be subjected to persecution.