A deathly silence hangs over the once lively trading town of Amchide in the far north of Cameroon, abandoned to the army by residents terrified of raids by the Islamists of Boko Haram.

After several attacks in the past year by the armed extremists from Nigeria, just across the western border, the vast majority of residents have fled.

Houses of clay and brick stand abandoned with nobody to cook in the courtyards, while colourful robes and children's laughter are things of the past.

The sole remaining human presence is a military one, dug in about 800 metres (875 yards) from the frontier and the lethal threat on the other side.

"Before, this was a bustling town, with crowds. Chadians, Cameroonians and Nigerians came here and traded in all kinds of things," said Abba, who comes from a nearby village.

Many people in Amchide ran the risk of atrocities and kidnapping by Boko Haram for months, but the situation further worsened when the Islamists in September overran Banki, the extension of their town on to Nigerian territory.

--'Firing almost every day'--

Boko Haram fighters then stepped up bloody raids inside Cameroon, where they slit the throats of Christians and Muslims alike. The movement also launched attacks from their positions in Nigeria.

"There is firing almost every day," an officer in Cameroon's elite military Rapid Intervention Battalion (BIR by its French initials) told AFP at the scene, asking not to be named for security reasons.

Several hundred metres (yards) from their main base, dozens of soldiers on high alert manned a forward post, some keeping a lookout behind piled sandbags. Others were poised to ambush intruders, wary of the surrounding savannah grass and trees that offer cover to Boko Haram forces.

On October 15, the Nigerian movement, which has frequently slaughtered students in its opposition to Western-style education, carried out an assault of "unprecedented scale" against Cameroon's army, said Major Leopold Nlate Ebale, chief of operations in the border zone.

Coming out of Banki, the Islamists struck at the military base with heavy artillery, while a suicide bomber drove a car loaded with explosives through Amchide. The car blew up on the outskirts of the base and was followed by an armoured vehicle and a pick-up truck, which were both "neutralised", Ebale added.

The fighting that ensued lasted for two days. The burned-out wrecks of the armoured vehicle and one of the others have been left standing by the entrance to the military base.

During the clashes, 107 members of Boko Haram were killed, together with 86 civilians and eight soldiers of the BIR, according to official figures that cannot be independently confirmed.

Military operations to "clean up" Amchide are a task rendered harder by the complexities of the border. "When you go into a house by a door in Cameroon, you can come out on the Nigerian side," where Islamists have many hiding places, an official said.

'They're like ghosts'

"Boko Haram (fighters) are unpredictable. They're like ghosts," one soldier said.

Cameroon's army states that in the absence of "a right of pursuit" into neighbouring countries, it will never carry out ground attacks on Nigerian territory. However, several officers agreed that "for protection in the event of aggression", they had the right to fire shells across the border.

The BIR responded to a Boko Haram attack last Monday by firing 36 shells, one of the officers said.

In villages of the district, people still try to live as normally as they can despite the sound of almost daily blasts and gunfire.

In Kourgui, about 20 kilometres (12 miles) from Amchide, "we're afraid that Boko Haram will come this far," elderly villager Oumate Mohamed said, sitting in the shade of a large tree.

In recent weeks, "many residents went through here, they were fleeing violence" closer to the border, Mohamed explained. Some decided to stop at Kourgui, but most headed on towards towns deeper into Cameroon.

In the arid border territory where growing millet and cotton are the main tasks for poor local people, the end to trade with Nigeria caused by conflict is a tough blow.

"Everything used to come from Nigeria before, even petrol, but we can't go there now," farmer Baba Chetima said, clad in a long white robe. "People have nothing left."