Northern Mali's largest city was rocked by a second suicide bombing and rebels clashed with Malian troops Sunday as Islamist militants defied a security lock-down on territory reclaimed by French-led forces.
A gunbattle between Malian soldiers and suspected Islamists erupted in the streets of central Gao near the main police station, an AFP correspondent said.
The clash, which sent residents running for cover, came after a bomber blew himself up late Saturday at the same army checkpoint where the first such attack in Mali occurred on Friday.
His severed head, still lying on the ground the next morning, was later picked up and placed in a wheelbarrow as French troops combed the site at the edge of Gao for landmines, uncovering several of the explosive devices, AFP correspondents said.
The suicide blasts underlined the threat of a drawn-out insurgency as France, whose warplanes were still bombing northern territory Sunday, 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 in March, claimed the first attack and had threatened 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, although one soldier was lightly wounded in Friday's bombing.
Troops have now placed two walls of sandbags at the checkpoint, cut down trees to increase visibility and set up heavy machine guns.
Malian troops and Islamist fighters exchanged gunfire after the blast, witnesses said, and French military helicopters could be heard in the air.
The army closed the road where the attack occurred, which leads north from Gao to Bourem and Kidal, two other key towns in the region.
French troops arrived at the scene in six armoured vehicles Sunday and worked to secure the area, uncovering several landmines.
To the northwest, French warplanes bombed a government building 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, a grave containing several bodies, including those of three Arab shopkeepers recently arrested by Malian troops, was discovered Friday, 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.
Mali imploded last year after a March coup waged by soldiers who blamed then-president Amadou Toumani Toure 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.
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.