An explosion that rocked the north Malian city of Gao late Saturday was a suicide bombing at an army checkpoint, the day after a similar attack at the same spot, said a Malian soldier, reporting no other wounded.
"It was a suicide bomber who blew himself up," said the soldier, who was at the checkpoint at the northern entrance to Gao, which French-led forces reclaimed from Islamist rebels on January 26.
The bomber's severed head was still lying on the ground at the scene Sunday morning.
The explosion shook the city, the largest in northern Mali, around 11:00 pm (2300 GMT) Saturday.
Troops from Mali and Niger had already increased patrols and fortified checkpoints with sandbags and heavy machine guns after Friday's suicide attack, in which a young Tuareg dressed in a paramilitary uniform drove up to the checkpoint on a motorcycle and detonated an explosive-rigged belt.
He failed to detonate a larger bomb he was carrying, and no one else was killed, though a Malian soldier was lightly wounded.
The attack was claimed by the Movement for Oneness and Jihad in West Africa (MUJAO), one of a trio of Islamist groups that seized control of northern Mali for 10 months.
In a new statement issued Saturday before the second suicide bombing, MUJAO had warned of new attacks.
"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.
On Sunday the army had closed the road where the blast occurred, which leads from northeastern hub Gao to Bourem and Kidal, two other key towns in the region.
After Friday's attack, the number of soldiers at the checkpoint had been doubled, two walls of sandbags placed 300 metres (yards) apart to protect them and surrounding trees cut down to increase visibility.