Kabul, Afghanistan ? NATO said Sunday that its two-week offensive in south Afghanistan was a “significant success” that had driven Taliban insurgents from their positions and opened the way for development.

But violence was unabated, with suicide bombers killing two civilians and wounding six soldiers.

Militants also took control of a district in the west of the country after chasing away the police, an official said, in an apparent attempt to open a new front.

The developments came as the country is going through its bloodiest phase since the U.S.-led invasion ousted the hard-line Taliban from power in 2001.

Lt. Gen. David Richards, head of the 20,000-strong NATO-led force in Afghanistan, said the insurgents have been forced out of the volatile former Taliban heartland, and reconstruction and development efforts there would soon begin.

Alliance officials have said more than 500 militants were killed during the two-week operation, centered mainly in Panjwai, Pashmul and Zhari districts of southern Kandahar province.

Two foreign military convoys in different areas of Afghanistan came under attack from suicide bombers, a method frequently used by insurgents in Iraq.

A 17-year-old youth carrying explosives jumped in front of a U.S. military convoy east of Kabul, killing a bystander, Afghan police said.

Earlier in the day, a suicide bomber plowed his explosive-laden vehicle into a Canadian military convoy west of Kandahar in southern Afghanistan, killing one civilian and wounding three soldiers, authorities said. Eight civilians also were wounded, said Zulmai Khan, a police official at the scene.

U.S. soldiers stand guard near a vehicle destroyed by a suspected suicide attacker near Kabul, Afghanistan. A youth carrying explosives jumped in front of a U.S. military convoy east of Kabul, killing a bystander and wounding three American soldiers on Sunday, Afghan police officials said.

Most of Afghanistan’s recent surge in violence has taken place in volatile southern provinces, where some 8,000 NATO forces took military control from the U.S.-led coalition on Aug. 1. NATO commanders say they need another 2,500 troops plus greater air support to crush the Taliban threat more quickly.

Richards said the end of the southern offensive should open the way for much needed reconstruction and development in areas where the central government has been unable to reach.

But some 400 heavily armed Taliban crossed into the western Farah province, taking control of its Gulistan district after chasing away the police and burning the district headquarters and a local clinic, provincial police chief Gen. Sayed Aqa Saqib said. No casualties were reported.

“We are hoping the government will send more troops, because there are too many Taliban in the area,” Saqib told The Associated Press over the phone.

Gen. Sher Mohammad Karimi, the Afghan army’s chief of operations, acknowledged that the Taliban “were not all destroyed” and that some have simply slipped away into other areas. “They may reorganize but our troops will follow,” Karimi said.

Richards ruled out immediately pursuing the Taliban holdouts.

“We will not dance to the Taliban’s tune,” Richards said. “They want to deflect us and take us away. We won’t let them do that.”