US President Barack Obama is lifting the two-year freeze on new military trials for detainees at the Guantanamo Bay prison.
Mr Obama also announced a new process for continuing to hold those detainees not charged or convicted but deemed too dangerous to free.
He said the measures would "broaden our ability to bring terrorists to justice".
Mr Obama had pledged in January 2009 to close the prison within a year.
"The American system of justice is a key part of our arsenal in the war against al-Qaeda and its affiliates," Mr Obama said in a statement.
http://www.bbc.co.uk/news/world-us-canada-12671777
Note:7 March 2011 Last updated at 21:52 GMT