Northern Mali's largest city was rocked by its second suicide bombing in two days, soldiers said Sunday, as Islamist rebels continued defying a security lock-down on territory reclaimed by French-led forces.
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.
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 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 two suicide bombers were the only fatalities in the attacks.
One soldier was lightly wounded in Friday's bombing. No one else was wounded in Saturday's, 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 after the first attack.
Malian troops and Islamist fighters exchanged gunfire after the blast, witnesses said, and French military helicopters could be heard in the air afterwards.
The army closed the road where the attack occurred, which leads from Gao to Bourem and Kidal, two other key towns in the region.
French troops arrived at the scene Sunday morning in six armoured vehicles and began securing the area, uncovering several landmines they said they planned to detonate in a controlled explosion.
To the northwest, French warplanes bombed a government building early Sunday in the town of Gourma-Rharous, between Gao and Timbuktu, 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."
-- Arab bodies found in Timbuktu --
With the Islamist insurgents on the run or underground, the north is being torn by tensions between light-skinned Arabs and Tuaregs -- accused of supporting the rebels, whose members were mostly drawn from the two groups -- and their black neighbours.
Residents of a village near Gao on Saturday detained an Arab and a Tuareg they claimed were strapped with explosives.
Friday's suicide attack was carried out by a Tuareg, and Saturday's bomber was either Arab or Tuareg, according to witnesses.
In Timbuktu, several bodies, including those of three Arab shopkeepers recently arrested by Malian troops, were discovered Friday in a grave in Timbuktu, reported Mauritanian online news agency ANI.
Rights groups have accused the Malian army of summary executions of Tuaregs and Arabs and called on the government to protect them from reprisal attacks.
After French-led forces captured Timbuktu on January 28, hundreds of residents looted Arab-owned shops, discovering arms and military equipment in some but also carting off merchandise such as TVs and food from others.
Mali imploded last year after a March 22 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 the southern government.
With the capital in disarray, Al-Qaeda-linked fighters hijacked the Tuareg rebellion and took control of the north, imposing a brutal form of Islamic law.
France launched its surprise intervention on January 11, and together with an African force eventually set to grow to some 8,000 troops, has pushed the insurgents from their main strongholds.
Many are believed to have fled to the Adrar des Ifoghas massif, a craggy mountain landscape in the far northeast near the Algerian border -- an area French warplanes have continued bombing 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.