Malians began voting on Sunday in the second round of parliamentary elections intended to cap the nation’s return to democracy, but overshadowed by the deaths of two UN peacekeepers in an extremist attack.

Malians began voting on Sunday in the second round of parliamentary elections intended to cap the nation's return to democracy, but overshadowed by the deaths of two UN peacekeepers in an extremist attack.

The polls mark the troubled west African nation's first steps to recovery after it was upended by a military coup in March last year, finalizing a process begun with the election of its first post-conflict president in August.

Turnout looked low as polling stations opened in the capital Bamako, sparking fears that voters would be scared away by an upsurge in violence by Al Qaeda-linked rebels against African troops tasked with election security alongside the Malian army.

Two Senegalese UN peacekeepers were killed and seven wounded on Saturday when a suicide bomber ploughed his explosives-laden car into a bank they were guarding in the northeastern rebel bastion of Kidal.

Sultan Ould Badi, a Malian jihadist linked to several armed groups, said the attack was in retaliation for African countries' support of a French-led military operation launched in January against extremist rebels in northern Mali, which ethnic Tuareg's call "Azawad".

"We are going to respond all across Azawad and in other lands... with other operations against France's crusades," he told AFP by telephone.

Senegalese President Macky Sall said the attack would "in no way undermine the strong commitment of Senegal to Mali" in a statement published by the state news agency APS.

"These two soldiers, killed in battle, had gone into Mali to defend democracy, freedom and peace," he added.

The French army has been carrying out an operation against armed extremists north of the desert caravan town Timbuktu over the past week.

The offensive targeting Al-Qaeda in the Islamic Maghreb (AQIM) is a "huge military operation, the largest in the Timbuktu region since the major northern cities were retaken by allied forces", an African military source in Timbuktu told AFP.

Twenty militants have been killed so far, according to French and African military sources.