The al-Qaeda-linked extremists overran the garrison village of Diabaly, in central Mali, France's defence minister, Jean-Yves le Drian, said in Paris.

Le Drian said yesterday that the rebels "took Diabaly after fierce fighting and resistance from the Malian army that could not hold them back".

The Malian military is in disarray and has let many towns fall with barely a shot fired since the insurgency began almost a year ago.

French military forces, who began fighting in Mali on Friday, widened their bombing campaign against Islamic extremists occupying northern Mali, launching airstrikes for the first time in central Mali.

The rebels, many of whom are not Malians, had been bottled up in the narrow neck of central Mali. But now, sweeping in from the west, they are only 400km from Mali's capital, Bamako, in the south. Before France sent its forces in, the closest the Islamists were to the capital was 680km but they might have infiltrated closer.

France is urging the "Africanisation" of the conflict, encouraging African nations to send troops to fight the extremists.

There have been promises but no troop deployments have yet been announced.

Yesterday, a French intelligence agent said shots rang out near the Diabaly military camp in what was still nominally government-held territory and, soon after, jets were heard overhead, and then a series of explosions.

A Malian commander in the nearby town of Niono said the bombing did not stop the Islamists and they occupied Alatona, and yesterday reached the north-south road that connects Diabaly to Segou, the administrative capital of central Mali.

The Islamist advance in central Mali was made after French fighter-bombers began dropping bombs on the rice-growing region of Alatona late on Sunday.

Mali's north, an area the size of France, was occupied by al-Qaida-linked rebels nine months ago, following a coup in the capital.

France has deployed 550 troops to Mali and authorised airstrikes, which began on Friday, at first concentrated in the north. The Mirage jets are stationed in Chad,

Britain is sending C-17 transport aircraft to help France bring in more troops and equipment.

The US is providing attack and reconnaissance drones, and communications, surveillance and logistical support.

Le Drian said a second French commando missing after a bungled attempt to rescue a hostage in Somalia, on the other side of Africa, was probably killed during the operation.

Somali insurgents al-Shabab - like the Islamists in Mali, linked to al-Qaeda - posted on Twitter two photos of a man wearing uniform trousers and a blood-soaked shirt.

Le Drian said France believed that al-Shabab was preparing a "disgraceful display" of the soldiers' bodies.