By Tiemoko Diallo

BAMAKO (Reuters) - At least five suicide bombers died in northern Mali on Friday in attacks aimed at Malian and Nigerien troops which failed to inflict serious casualties on their targets, a spokesman for Mali's army said.

One of the towns hit was Gossi, the furthest south al Qaeda-linked Islamist rebels have struck in a guerrilla war launched against Malian and regional forces since the rebels were driven from their former strongholds in a French-led offensive this year.

The attacks have had limited success so far but threaten to undermine international calls for elections to be held across Mali in July although security is not yet fully restored to a zone that was occupied by Islamists last year.

The suicide raids took place nearly simultaneously between 4 and 5 a.m. in Menaka and Gossi, near Gao.

"The first attack targeted Nigerien soldiers in Menaka. A car bomb entered the (military) camp, but the soldiers ... destroyed the vehicle, which exploded," Lieutenant Colonel Souleymane Maiga told Reuters.

"At the same time in Gossi, three suicide bombers on foot attacked a checkpoint. Again the soldiers ... shot them. The three bombers were killed," he said.

As the men exchanged fire with soldiers, a fourth member of the group entered a nearby military camp and blew himself up, slightly wounding two soldiers, a second military source said.

A bus driver passing through Gossi, 150 km (90 miles) southwest of Gao, told Reuters he saw dismembered body parts strewn along the road, which links Gao and the capital Bamako.

Hours after the attacks, France's President Francois Hollande and Niger's President Mahamadou Issoufou reiterated calls for elections due in July to be held across the entire country.

"No part of Mali should be deprived of the possibility of organizing an election," Hollande told journalists.

For this to happen, security forces will have to fend off further attacks by militants, who have struck in Gao, Kidal and Timbuktu - northern Mali's three main towns - and resolve a standoff in Kidal, which is still occupied by a mix of Tuareg-led separatist and Islamist rebels.

Bamako has said an offensive on the town is imminent but rights groups warn such an operation could lead to reprisal killings. Diplomats say they are seeking a solution that will allow elections to take place in Kidal and then talks organized between the rebels and a new elected government.

Thousands of regional troops have been sent to Mali in the wake of the largely successful French offensive.

Paris is looking to withdraw thousands of troops from its former colony and hand over security duties to a 12,600-strong United Nations peacekeeping force to be established from July 1.

Underscoring Mali's needs, the government will next week ask donors for nearly two billion euros ($2.6 billion) to help rebuild the country and try to prevent rebels again taking advantage of a weak state.

(Additional reporting by Adama Diarra, Adrian Croft in Brussels and Elizabeth Pineau in Paris; Writing by David Lewis and Joe Bavier; Editing by Andrew Roche)