Egypt's President, Mohammed Mursi, has pardoned all those arrested since the beginning of last year's popular uprising that ousted Hosni Mubarak.
A post on the president's official Facebook page announced an amnesty for crimes and misdemeanours committed "in support of the revolution".
The decree could lead to the release of several thousand people.
Mubarak stood down in February last year following 18 days of unrest during which hundreds of protesters died.
He is currently serving life in prison after being found guilty in June of failing to prevent the killings.
The "comprehensive pardon" announced by the new president on Monday applies to anyone who was charged with or convicted of "crimes and misdemeanours or attempts to commit them in support of the revolution and the realisation of its goals".
The pardon applies to all those arrested from 25 January 2011, the first day of the revolution, until 30 June 2012, when Mr Mursi took office.
It covers those who are awaiting trial as well those already serving jail sentences. The only exception will be those accused of murder.
Most of those on trial or convicted were detained during the 16 months that Egypt was ruled by the Supreme Council of the Armed Forces, which assumed presidential powers after Mubarak stepped down.
More than 12,000 civilians were brought before military tribunals during that time and the campaign group, No to Military Trials, has said that at least 5,000 political prisoners are still in jail.
Mr Mursi's legal adviser, Mohammed Gadallah, said the amnesty was "one of the revolution's most important victories".
"It shows the revolution is now in power and guides the decision-making," he told the Associated Press. "This is a legislation that protects the revolutionaries."
However, human rights lawyers said the wording of the decree was vague and did not immediately set anyone free. It says the names of those to be pardoned must be published by the attorney-general and the military prosecutor within a month. Those not named can challenge the decision.
"It is a great step, but not enough," said Ahmed Seif, a member of the committee formed by Mr Mursi to review cases of those put on trial. "There will be differences over how to implement the pardon."
Ahmed Ragheb, another human rights lawyer, told AP that the phrase "in support of the revolution" could be interpreted in different ways.
Mr Gadallah acknowledged that it was not clear how many people would benefit from the pardon, but said it was likely to cover all major cases where protesters had clashed with security forces.
A month after winning Egypt's first democratic presidential election, Mr Mursi pardoned more than 500 civilians convicted by military tribunals.