Protesters gather on Tunis 'main avenue after a Tunisian opposition leader critical of the Islamist-led government was gunned down as he left home Wednesday, Feb.6, 2013. Chokri Belaid was gunned down as he left home in the first assassination in post-revolutionary Tunisia. The killing of Belaid, a 47-year-old lawyer, heightens tensions in the North African nation whose path from dictatorship to democracy has been seen as a model for the Arab world so far. (AP Photo/Hassene Dridi)

Associated Press
Protesters gather on Tunis 'main avenue after a Tunisian opposition leader critical of the Islamist-led government was gunned down as he left home Wednesday, Feb.6, 2013.  Chokri Belaid was gunned down as he left home in the first assassination in post-revolutionary Tunisia. The killing of Belaid, a 47-year-old lawyer, heightens tensions in the North African nation whose path from dictatorship to democracy has been seen as a model for the Arab world so far. (AP Photo/Hassene Dridi)
Protesters gather on Tunis 'main avenue after a Tunisian opposition leader critical of the Islamist-led government was gunned down as he left home Wednesday, Feb.6, 2013. Chokri Belaid was gunned down as he left home in the first assassination in post-revolutionary Tunisia. The killing of Belaid, a 47-year-old lawyer, heightens tensions in the North African nation whose path from dictatorship to democracy has been seen as a model for the Arab world so far. (AP Photo/Hassene Dridi)