The Tunisian government has published the names and photographs of five people it said were suspected of involvement in the February assassination of a secular opposition politician and asked citizens to help track them down.
The killing of Shokri Belaid on February 6 provoked the worst unrest in the North African state since the overthrow of strongman Zine al-Abidine Ben Ali two years ago that launched the Arab Spring wave of popular uprisings.
"We ask all citizens to contribute to the search for the main suspect and the rest of those involved in the assassination of the martyr Shokri Belaid," the interior ministry said in statement on Saturday.
One of the men was shown with and without a beard.
The ministry's website posted the names and pictures of five men and pledged to provide protection and confidentiality for anyone who helped locate suspects in the killing.
Police believe Belaid's killer was a member of a radical Salafist group who is on the run, Prime Minister Ali Larayedh said recently, without giving more details.
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The government, led by the Islamist Ennahda movement, had been under intensifying public pressure to take concrete steps to arrest suspects in the assassination.
No one has claimed responsibility so far.
Ennahda has denied accusations by some, including Belaid's brother, that it was involved in the shooting death, which it has condemned.
Protests after the assassination of Belaid ended with the resignation of the government of Ennahda's Hamadi Jebali.
Larayedh, also from Ennahda, succeeded him and formed an uneasy coalition with two secular parties.
Tunisia's political transition from popular upheaval has been more peaceful than in neighbouring Egypt and Libya. But tensions have risen between Islamists freely elected to power and liberals who fear the loss of hard-won individual liberties.
Since Ben Ali's fall, the struggle over the role of religion in government and society has emerged as the most divisive issue in Tunisia, which for decades was considered among the most secular countries in the Arab world.