Kandahar, Afghanistan ? Afghan and NATO troops used rockets, planes and artillery in rolling battles with Taliban insurgents this weekend in Afghanistan’s volatile south, leaving 71 militants and five Afghan soldiers dead in one of the bloodiest clashes since the 2001 U.S.-led invasion. A British soldier was killed in a separate attack.

The fierce fighting began late Saturday and continued into Sunday after the Taliban attacked a police convoy in Kandahar province’s Panjwayi district, said Niaz Mohammad Sarhadi, the district government chief.

In the neighboring southern province of Helmand, a separate clash Sunday with insurgents left one British soldier dead and three others wounded, Britain’s defense ministry said. The death brought to 20 the number of British soldiers killed since they deployed to Afghanistan in November 2001.

Militants also ambushed a police patrol in the western province of Farah, sparking a gunbattle that left one officer and two attackers dead, a regional governor said.

Afghanistan’s southern provinces are bearing the brunt of the worst bout of violence since U.S.-led forces toppled the hard-line Taliban regime. Taliban holdouts and allied extremists have stepped up attacks in a bid to undermine the American-backed government of President Hamid Karzai.

In Panjwayi, NATO troops used artillery and aircraft to inflict “heavy casualties against Taliban fighters,” an alliance statement said.

“It was a sizable engagement,” said Toby Jackman, a NATO force spokesman. He called the clash part of an ongoing operation “to extend security” along the 260-mile highway between Kabul and Kandahar.

The bodies of 71 slain militants were found in three locations, scattered through orchards alongside their weapons, Sarhadi said.

“The police are still searching for more dead bodies of Taliban,” he said.

Four police and one Afghan soldier also were killed in the clashes, officials said. Three police and five soldiers were wounded and three police were missing.