Spain is prepared to accept prisoners from the United States detention camp at Guantanamo Bay.
After a meeting with US Secretary of State Hillary Clinton on Tuesday, Foreign Minister Miguel Angel Moratinos said Spain would study possible transfers on a case-by-case basis.
He said Spain was open in principle to receiving some prisoners provided the legal conditions were acceptable.
The US holds about 250 prisoners at Guantanamo.
Last month, US President Barack Obama set a one-year deadline for closure of the camp.