KABUL, Afghanistan — A joint Afghan-NATO operation in a volatile region in the country's dangerous south has killed 40 militants, including the Taliban's leader in that region, a government official said Monday.

The fighting came as Britain's leader Gordon Brown announced 300 more British troops were deployed to Afghanistan.

The operation in the Nad Ali and Murja districts of Helmand province began on Thursday and continued through Monday, said Dawood Ahmadi, spokesman for Helmand's governor.

Ahmadi said 40 militants were killed, though he said government officials recovered only seven bodies, which were given to tribal elders for burial. Ahmadi said the government knows another 33 fighters were killed through intelligence sources.

The figures couldn't be independently verified. Lt. Cmdr. James Gater, a spokesman for NATO's International Security Assistance Force, confirmed that a joint operation in Helmand was under way. He said he had no casualty figures he could release.

Among the dead was a Mullah Salim, a Taliban leader who was the head of the militant's council in the two districts, Ahmadi said. The councils, also called shuras, are sometimes referred to as a shadow government structure that operates separately from the Afghan government.

Afghan officials admit they have little control in many areas of northern Helmand, a poppy-growing region that is heavily infiltrated by Taliban fighters.

Violence has spiked across Afghanistan the last two years. More than 6,000 people have died in insurgency-related violence in 2008, according to an Associated Press count of figures based on Afghan and Western officials.

Brown said Monday that Britain has sent 300 more troops to Afghanistan to bolster efforts against the resurgent Taliban — but declined to confirm whether he'll offer larger numbers of extra soldiers to support an expected U.S. military surge next year.

Brown, who visited Afghanistan, India and Pakistan over the weekend, said other NATO allies — including Britain's European neighbors — should take on a greater combat burden if the international mission is expanded.

The United States plans to send about 20,000 more soldiers into Afghanistan next year, aimed at stemming terrorism and providing security for the country's presidential elections next autumn.

"The burden is not always shared equally," Brown said. "It is vital that all members of the coalition contribute fairly."

A total of 41 countries are involved in the military mission in Afghanistan. Canada, Italy and France each contribute about 2,500 troops, and the Netherlands 1,700. Dozens of other nations provide smaller numbers.