Northern Mali's largest city was rocked by its second suicide bombing in two days, a soldier said Sunday, as Islamist rebels continued defying a security lock-down on territory reclaimed by French-led forces.
The twin suicide blasts, the first such attacks in Mali, underlined the threat of a drawn-out insurgency as France, whose warplanes were still bombing northern territory Sunday morning, tries to map an exit strategy nearly one month into its intervention in its former colony.
The bomber blew himself up late Saturday at the same army checkpoint in Gao where the first such attack occurred the day before.
His severed head was still lying on the ground Sunday morning.
Witnesses said Malian troops and Islamist fighters had also exchanged gunfire after the blast. French military helicopters could be heard in the air after the bombing.
No one else was wounded in the attack, said a soldier at the checkpoint, where troops had already placed two walls of sandbags, cut down trees to increase visibility and set up heavy machine guns to protect themselves after Friday's attack.
The Movement for Oneness and Jihad in West Africa (MUJAO), one of the Islamist groups that seized control of northern Mali for 10 months in the wake of a military coup, claimed the first attack and had threatened earlier Saturday that there would be more.
"We are dedicating ourselves to carrying out more attacks against France and its allies. We ask the local population to stay far away from military zones and avoid explosions," spokesman Abou Walid Sahraoui said.
The army closed the road where the blast occurred, which leads from Gao to Bourem and Kidal, two other key towns in the region.
French warplanes bombed a government building early Sunday morning in the town of Gourma-Rharous, between Gao and Timbuktu to the northwest, a local official said.
The building "held vehicles and military equipment belonging to the Islamists," the official said on condition of anonymity. "Three Islamist vehicles were destroyed."
The latest attack came as a report said several bodies, including those of three Arab shopkeepers recently arrested by Malian troops, had been discovered in a grave in Timbuktu.
The discovery was made Friday, Mauritanian online news agency ANI reported.
Timbuktu has been the scene of reprisal attacks by black Malians against Arab and Tuareg residents accused of supporting the Al-Qaeda-linked Islamist rebels.
Rights groups have already accused the Malian army of summary executions of Tuareg and Arabs and called on the government to protect them from reprisal attacks.
In the capital Bamako, a firefight Friday between rival army units killed two adolescents and wounded another 13 people, showing the deep divisions in the Malian military.
Paratroopers loyal to ex-president Amadou Toumani Toure, ousted in a March 2012 coup, were protesting an order absorbing them into other units to be sent to the frontline when the gunfight erupted.
The fighting overshadowed the arrival of 70 EU military trainers, the first of what is to be a 500-strong mission tasked with whipping the Malian army into shape.
The nation imploded last year after the coup, waged by soldiers who blamed the government for the army's humiliation by a separatist rebellion among the Tuareg, a North African people who have long complained of being marginalised by Bamako.
A month later, paratroopers launched a failed counter-coup that left 20 people dead.
With Bamako in disarray, Al-Qaeda-linked fighters hijacked the Tuareg rebellion and took control of the north, imposing a brutal form of Islamic law.
French special forces and Chadian troops on Friday secured the strategic oasis of Tessalit, near the Algerian border in the far northeast, and sought to flush the Islamists out of hiding in the Adrar des Ifoghas mountains, where they are believed to have fled with seven French hostages.
French warplanes have continued bombing the area in recent days.
But the frontline is blurry, and the Islamist militants have turned to guerrilla tactics.
Two Malian soldiers and four civilians have already been killed by landmines, and French troops are still fighting off what Paris called "residual jihadists" in reclaimed territory.