Cameroon said at least 91 civilians have been killed by Boko Haram since the Nigerian militants invaded Cameroonian villages on Wednesday.
Defense Minister Edgard Alain Ngo told VOA reporter Moki Edwin Kindzeka that six Cameroonian soldiers and 13 Chadian soldiers have also died in clashes with gunmen in and around the border town of Fotocol.
The minister said at least 500 people have been wounded, adding the death toll may increase because most of the wounded have not been taken to hospitals.
Chad and Cameroon have deployed troops to fight Boko Haram amid concerns the radical Islamist group has become a regional threat.
On Tuesday, Chad said its forces repelled a Boko Haram attack on Fotocol and chased the militants across the border to the Nigerian town of Gambaru.
Cameroon government spokesman Issa Tchiroma Bakari said the militants took heavy casualties when they attacked Fotocol again on Wednesday.
"After fierce fighting, the enemy was once more booted out, incurring over more than 50 deaths among its troops," Bakari told VOA. "The response of our army led to the seizing of huge war materiel," said Bakari.
More fighting was reported around Fotocol on Thursday. Bakari said the fighters have burned churches, mosques and villages and looted livestock and food.
France seeks international support
Meanwhile, French President Francois Hollande called on the international community to help fight extremism in Africa, instead of talking on the sidelines.
France is supporting operations against Boko Haram by carrying out reconnaissance flights over border areas of Chad and Cameroon to provide the two nations with intelligence, defense officials in Paris have said.
Fighting in northeast Nigeria has escalated as the country's February 14 presidential election draws closer. Regional concerns grew when Boko Haram seized a multi-national military base on the shores of Lake Chad in early January.
Rights group Amnesty International said the militants burned down thousands of buildings in the town of Baga and areas nearby.
Boko Haram has been seizing territory in northeastern Nigeria for what it calls an Islamic caliphate.
Plans are under way to set up a force of 7,500 soldiers to combat Boko Haram, which is blamed for thousands of deaths since launching its insurgency in 2009. Chad, Cameroon, Niger and Benin have pledged to contribute troops to the force.
On Tuesday, Nigerian government spokesman Mike Omeri told VOA that Chad is operating under a bilateral protocol that allows it to pursue Boko Haram fighters into Nigerian territory.
Some material for this report came from AP and AFP.