DIKWA, Nigeria (Reuters) - A black and white Boko Haram flag still flutters on top of a deserted villa in the Nigerian town of Dikwa, overlooking a courtyard filled with dirty mattresses and charred vehicles.
Inside the villa's pink and white walls, blood trickled into corridors and a pile of insurgents' bodies lay in a heap in a wardrobe.
The scene was the result of a dawn attack by troops from neighboring Chad, who are driving deep into Nigerian territory in an offensive aimed at helping end a six-year insurgency that has killed thousands and now sucking in neighboring armies.
"They resisted ferociously. This huge villa was their command center," a Chadian soldier who fought in the battle told a Reuters reporter visiting the town after fighting subsided.
Colonel Azem Bermandoa, a Chad army spokesman, said more than 100 of the militants died in the battle for Dikwa, a town at a major crossroad some 80 km (50 miles) east of Maiduguri, the capital of Nigeria's northeastern Borno state.
"They came to hide here as we advanced," another Chadian soldier said, pointing to the bodies in the wardrobe.
In an apparent last act of defiance, a Boko Haram suicide bomber climbed into a truck carrying gas canisters and blew it up, killing one Chadian soldier and injuring 34.
Bermandoa said Chadian troops chased the remaining fighters about 15 km out of the town, where many walls are now sprayed with bullets and most houses lie deserted.
In this part of Nigeria - until now, Boko Haram's heartland - residents have learned to flee the Sunni militants' bid to carve out an Islamic caliphate.
But the tide finally appears to be turning against them as Chad has spearheaded a regional push against the group and Nigerian forces notch up some military gains as well.
Chad's victory at Dikwa is one that Nigeria would have like to have called its own. Its army chief previously said his soldiers listed Dikwa as a town that troops wanted to recapture before elections, due to have been held in February but pushed back to March due to insecurity.
Chadian forces had planned to take the town last month, but were ordered back by Nigeria, which said it planned to attack it. But a Chadian soldier in Dikwa said the closest Nigerian soldiers got to the town during Monday's fighting was 50 km away.
Chad's army, considered one of the best in the region and backed by a strong air force, first deployed to help Cameroon fend off Boko Haram and is now pressing southwest into Nigerian territory after capturing the border town of Gambaru last month.
That victory starved Boko Haram militants of supplies, said Ryan Cummings, chief Africa analyst at crisis management group Red24.
"The major challenge that the Nigerian army faced was that Dikwa served as forward base for Boko Haram and was readily being supplied with resources and combatants from Boko Haram positions along the Nigeria-Cameroon border," he said.
But despite these recent setbacks, Boko Haram has proven it is still able to carry out isolated attacks.
Two security sources said Boko Haram attacked Kaiga on Lake Chad at the weekend. They arrived in canoes and burned houses, but it was not immediately possible to confirm a number of casualties.
Cummings added that losing key towns did not necessarily mean the end of Boko Haram, which long before beginning to control territory, waged a guerrilla war involving raids and car bombing.
"Even if the combined forces are successful in dislodging Boko Haram from its regional strongholds, this may not bring about regional stability," he said.
Additional reporting by Julia Payne in Abuja, writing by Emma Farge; editing by David Lewis, G Crosse