Ten French soldiers are dead and 21 injured after a battle with Taliban insurgents outside Kabul, in what is reportedly the biggest single loss of life during combat suffered among international forces in Afghanistan in three years.

The French soldiers were members of the 8th infantry parachute regiment. They were attacked while on a reconnaissance mission in a known militant stronghold, say military officials.

An Afghan official told the Associated Press that four of the 10 soldiers were first kidnapped by insurgents and then killed.

Sources told AP the battle took place over two days in the Surobi district of Kabul province, about 50 kilometres outside of the Afghan capital.

Qazi Suliman, the district chief in Surobi, said 13 insurgents also died in an ensuing three-hour gun battle. NATO said it sent reinforcements and a "large number" of the 100 attackers died.

Meanwhile, an Afghan intelligence officer told the BBC that the soldiers were "ambushed in a village" from "several directions."

The officer said the Taliban used heavy machine guns and other weapons to attack the soldiers.

French President Nicolas Sarkozy said Tuesday he will travel to Afghanistan immediately following the incident.

"My determination is intact. France is determined to continue the struggle against terrorism for democracy and freedom. The cause is just," Sarkozy said in the statement.

The latest deaths bring the total number of French troops killed in Afghanistan to 22. The attack marks the deadliest against international troops in the country since June 2005, when 16 U.S. troops were killed in Kunar province when their helicopter was shot down by a rocket-propelled grenade.

Harper's response

In response to the deadly incident, Canada's Prime Minister Stephen Harper offered condolences to France over the loss of its soldiers. He said the loss of lives is sad, but that all NATO countries in Afghanistan must stay the course so that a stable environment can be accomplished.

Speaking in Hamilton, Ont. on Tuesday, Harper said Canadians have over the past several years understood the difficulty of the mission, and that Canada is proud to have the French making an enhanced contribution in Afghanistan.

Karzai may run again

Meanwhile, Afghanistan's President Hamid Karzai has told The Associated Press that he would like to seek re-election next year.

He said Tuesday that he has a job to complete, so "in that sense, yes, I would like to run."

Karzai has headed Afghanistan's government since the Taliban were toppled in late 2001. He served first as chair of the Transitional Administration then interim president.

On Dec. 7, 2004, Afghan's electorate elected Karzai, an ethnic Pashtun, as president for a five-year term.

Although he has hinted at a re-election run in 2009, this is the first time Karzai has addressed the issue directly.

Karzai, 50, is considered a staunch ally of the NATO presence in Afghanistan, but has been critical of civilian deaths resulting from counterinsurgency combat operations.

With files from The Associated Press