Ethiopian authorities have released 2,417 people who were detained last week during opposition protests.
It is not known how many have been arrested
Police said they were being released because they were not directly connected with the violence, in which more than 40 people died.
It is unclear how many people remain in detention. They include the leadership of the opposition Coalition for Unity and Democracy (CUD).
The trouble began after the opposition accused the government of poll fraud.
Protests in Sub-Saharan Africa's second most populous country were initially ignited after the 15 May polls, when some 36 people died and hundreds were arrested.
Last week's protests began after the CUD refused to attend parliamentary sessions.
On Wednesday, Prime Minister Meles Zenawi said the CUD leaders were likely to face treason charges for trying to overthrow the government.
If found guilty they could face the death penalty, but the prime minister said personally he did not support the death penalty.
The international community has called for the immediate release of all political detainees.
Mr Meles' Ethiopian People's Revolutionary Democratic Front won a majority in polls but the opposition gained many seats.
The opposition is made up of the two broad groupings - the CUD and the United Ethiopian Democratic Forces, which unlike the CUD, have taken up their parliamentary seats.