Teams of fraud poll investigators in Ethiopia have begun visiting the 135 constituencies where the result of May's election is fiercely disputed.
At least 500 opposition members remain in jail
At least 36 people were killed and thousands arrested in protests over the poll, won by the governing party of Prime Minister Meles Zenawi.
Opposition parties say many of their members are still in prison.
The 26 teams fanning out across the country include representatives from political parties.
Each team will also have two representatives from the National Electoral Board, as well as international observers.
They will spend about three days in each location, calling witnesses and hearing complaints about the way the election was conducted.
International observers will be supplied by the African Union, the Carter Centre and the European Union (EU).
The opposition parties are still angry that a large number of their members are still imprisoned.
Although about 3,800 have been released it is believed that at least 500 remain in jail.
The opposition Coalition for Unity and Democracy complains that it is unable to field its key activists because they have not been released.
Meanwhile, head of the EU mission to Ethiopia, Tim Clarke, had a meeting with Prime Minister Meles on Thursday.
One of the key issues they discussed was freedom of the press.
The prime minister agreed to publish the editorial guidelines covering the media, so that they were clear for all to see.
There is also an initiative to try to reduce tension between the opposition and the ruling Ethiopian People's Revolutionary Democratic Front over the words they use.
A set of guidelines are being drawn up which will try to end what is being termed "hate language".
"It is an attempt to end unnecessary unpleasantness," said Mr Clarke.