A Nigerian armored personnel carrier spattered with blood, riddled with bullets and towed into an army base in northern Cameroon is a potent reminder of Boko Haram's ability to strike across borders in its six-year war for an Islamic state.
Islamist militiamen captured the vehicle when they overran Gwoza, a town in northern Nigeria, last year. It still bears the insignia "PMF Training College, Gwoza" along its flank, partially obscured by Boko Haram scrawled in Arabic.
On Monday, guerrillas used the carrier to ambush an army patrol near Waza, a town on the Cameroon side of the border, killing five and wounding seven before launching an all-out assault on a nearby Cameroonian army camp.
After a fire-fight lasting nearly three hours and involving heavy and long-range artillery, Cameroonian soldiers repulsed the attack, leaving 94 Boko Haram fighters dead, according to officials.
Farmers discovered eight more bodies in fields on Tuesday, when Reuters visited Waza with a Cameroonian military patrol.
A pool of blood and dozens of spent cartridges lay on the floor of the armored personnel carrier, whose side windows had pierced by several heavy machine-gun rounds. The vehicle was towed into the Waza encampment after the battle.
"The combat was of a rare intensity. This was something we had not witnessed before," said Major Oumar Nchankou, head of Cameroonian special forces in Waza, who was lucky to escape alive after two rockets hit his vehicle in the initial ambush.
Nchankou was shot in the knee by a Boko Haram militant just 10 meters away but is still able to walk, albeit with a limp.
"It showed that we are fighting an enemy that knows what it is doing," he told reporters in Maroua, the regional capital.
Boko Haram has killed thousands and captured hundreds in Nigeria in the past year, but is now expanding its attacks into Cameroon, Niger and Chad as part of a six-year insurgency threatening the entire Lake Chad region.
The African Union has authorized a five-nation force, including Cameroon, to fight back.
Waza lies in a savannah national park surrounded by hills and used to be one of the top tourist destinations in Cameroon, a central African country that produces cocoa, timber and oil.
Militants began infiltrating the area in February 2013 with the kidnapping of a French family. In May they kidnapped 10 Chinese workers near the park.
Boko Haram covets the town as part of a strategic supply corridor as they come under pressure from Chadian forces to the north and Cameroonian government forces to the south, said Captain Ndema William, deputy commander in Waza.
Before dawn on Feb. 4, some 1,000 militants raided the town of Fotokol, 50 km (30 miles) north from Waza, slipping between lines of Chadian troops who had crossed from Cameroon into the Nigerian town of Gambaru.
Some struck from the north, others tried to storm the Elbeid bridge linking Gambaru and Fotokol, while a third group crossed the dry river bed separating the two towns, witnesses said.
"Around 5.30 am, we heard them screaming 'Allah Akbar' (God is Great). Then some of them burst into the mosque and started shooting," said Mohammed Bulma, a farmer whose house is next door to the mosque and who had answered the call to prayer.
Bulma fled by a side door but 37 people were killed inside, including the Imam, his three brothers and a nephew. The main streets of the border town are now empty. Shops have been razed and burnt cars and bullet casings litter the streets.
Cameroon's army is reinforcing in Fotokol, setting up a base, digging trenches, erecting sandbags at crossroads and installing mortars and other heavy weapons at the northern entrance of town to secure the bridge.
Many civilians have fled but Bulma is determined to stay, and says he feels safe.
"I have no where else to go. I have been here all my life," he told Reuters. "Boko Haram is not going to drive me away."