Thirteen Chadian soldiers were killed in fighting in northern Mali on Friday, the heaviest casualties sustained by French and African troops since the launch of a military campaign against Islamist rebels there six weeks ago, Chad's army said.
Chadian troops killed 65 al-Qaida-linked fighters in the clashes that began before midday in the Adrar des Ifoghas mountains near Mali's northern border with Algeria.
"The provisional toll is ... on the enemy's side, five vehicles destroyed and 65 terrorists killed. We deplore the deaths of 13 of our valiant soldiers," said a statement from the army general staff read on state radio.
France intervened in its former West African colony last month to stop a southward offensive by Islamist rebels who seized control of the north last April.
Troops from neighboring African nations - including 2,000 soldiers from Chad - have since deployed to Mali and are meant to take over leadership of the operation when French forces begin a planned withdrawal next month.
But continuing violence since the Islamists were driven from major urban areas highlights the risk of French and African forces becoming entangled in a messy guerrilla war as they try to help Mali's weak army counter bombings and armed raids.
Reporting by Madjiasra Nako; Writing by Joe Bavier; Editing by Jon Hemming and Peter Cooney
Copyright 2013 Thomson Reuters. Click for restrictions.

I'm faster than Wilson Arden.
13 to 65.
Ummmmm. That is not Gorilla warfare. That is open combat.
Gorilla warfare is the enemy hitting and running . trying to wear down superior numbers.
Hang in there Chad.
"But continuing violence since the Islamists were driven from major urban areas highlights the risk of French and African forces becoming entangled in a messy guerrilla war as they try to help Mali's weak army counter bombings and armed raids."
Those, who have closely followed Iraqi wars and Afghan wars, would understand that this battle with Sunni Islamic extremists in Mali and nearby areas is going to be very messy and long drawn.
Whole militant areas (where Islamist guerrilla's hide) need to be carpet bombed before troops get in or else they will get stuck badly as in Afghanistan.
Followers of Islamic cult, especially House of Saud and other Sunni ME rulers inspired and funded Sunni Islamic radicals and militants (al-Qaida, Salaffi, Wahhabi, MB, Taliban and other label ones), are fast marching backwards to their seventh century desert tribal days.
They are indulging in rapings, lootings, killings and genocides of non-Muslims (Darfur, S. Sudan, Nigeria and spreading like wild fire in many regions and Muslims (Libya, Yemen, Mali, Iraq, Syria, Pakistan, Afghanistan and other places).
Pakis and Sunni rulers of Saudi Arabia, Qatar, Kuwait, UAE and other Sunni Arab League nations are responsible for 80 percent of world problems including economic ones.
Examine the devastations with Iraqi wars and now sanctions on Iranian oil and the resultant oil price manipulations.
For world peace and economic stability, we will have to wipe out Saudi Arabia and Pakistan from the map.
For a sart, declare them as terrorist nations.
Gotit.. 13 Chad soldiers, 65 Islamists
guess the islamist were just standing on the corner shooting dice..
They should unleash the dogs of war: Zie Germans. Problem solved.
A brilliant victory for our boys in Eastasia; now go back to work peasants.
Flying over mosques and dropping pornography from the air after Friday prayers, with a follow-up ground crew collecting abandoned Kalashnikovs?
Ration cloth?
Running through the streets hollering at their wives and daughters: "Show me your pits!" ?
On and on it goes. Islamist have but one goal, to spread Islam and Sharia law world wide. They will never stop trying to reach that goal and spread death and destruction with their efforts. There is no way to reason with them, their brains are fevered with self righteousness and hatred for all that are not like them. Sooner or later the world will have to find a way to end their reign of terror.
The US really did the world a favor by training the mujahideen to fight the Russians in Afghanistan. Now they are able to train the Taliban and al-Qaida to fight everybody with effectiveness. Maybe the US should just stay out of other people's business.