Tunisians vote in the second round of a presidential election on Sunday, capping off four years of a sometimes chaotic transition since their country sparked the Arab Spring.

Incumbent Moncef Marzouki faces political veteran Beji Caid Essebsi in the vote -- the first time Tunisians will be allowed to freely elect their president since independence from France in 1956.

Tunisian Foreign Minister Mongi Hamdi has been appointed to head the U.N. peace mission in Mali, where 31 peacekeepers have been killed in attacks since it deployed 18 months ago.

Tunisia's former premier and Ennahda secretary general Hamadi Jebali announced on Facebook Thursday that he was stepping down from the Islamist party as he no longer agreed with its policies.

Jebali, who had already distanced himself from Ennahda, said he had joined the movement in the early 1970s in the name of "freedom and justice" against "tyranny and corruption."

Moncef Marzouki and Beji Caid Essebsi are to face off on December 21 in Tunisia's second round of presidential voting to decide who leads the nation that sparked the Arab Spring.

"Voting will take place on December 21," the head of the ISIE electoral organizing body, Chafik Sarsar, told a news conference on Monday.

Libya's internationally recognized government has given its backing to U.N.-brokered talks between warring factions aimed at halting unrest across the country, its foreign minister said late Thursday.

U.N. Special Representative Bernardino Leon in Libya chaired a first round of talks between rival politicians in the oasis town of Ghadames in September, and will lead a new round of negotiations on December 9.

Sudan's foreign minister accused "foreign parties" of fueling fighting in Libya as he opened a meeting of neighboring countries Thursday aimed at ending more than three years of violence.

Libya has been gripped by lawlessness ever since the 2011 overthrow of Moammar Gadhafi and is awash with weapons left over from the NATO-backed uprising against his dictatorship. Rival governments and parliaments dispute power, with swathes of territory in the hands of powerful militia.

Tunisia's first parliament since the 2011 revolution on Thursday elected veteran politician Mohamed Ennaceur, 80, of anti-Islamist party Nidaa Tounes as house speaker.

Ennaceur, the sole candidate, won 174 votes from the 214 MPs in attendance.

Tunisia's new parliament held its inaugural session on Tuesday, a landmark in the country's often fraught transition to democracy since the 2011 revolution which sparked the Arab Spring.

After the singing of the national anthem, National Constituent Assembly (NCA) speaker Mustapha Ben Jaafar opened the gathering of 217 members of parliament who were elected in October. 

A Tunisian soldier was killed in the southern region of Kef, the defense ministry spokesman told AFP.

He was killed in a mine explosion while carrying out an operation in the area.

"Terrorists" in Tunisia have abducted and decapitated an off-duty policeman, media reports on Monday cited the interior ministry as saying.

The officer and his brother were in a car in the Kef area of the northwest when gunmen seeking to rob them immobilized the vehicle.