He said assassinations have increased in Kandahar as insurgents make the point they can still operate despite the extra security.

NATO and Afghan patrols are stepping up patrols around Kandahar province to pressure insurgents in rural areas. The strategy is to improve security with more and better-trained police and troops so that capable governance can take root and development projects can move forward and win the loyalty of ordinary Afghans.

The Taliban have responded by ratcheting up suicide attacks and bombings.

Army Brig. Gen. Ben Hodges, a top US commander in southern Afghanistan, said Wednesday that the new Kandahar operation is still in its early stages and security will begin to improve in coming months as additional American and Afghan forces move into violent areas.

"It's a rising tide," he said. "And that tide is starting to come in now. We're going to start feeling those positive effects here as July turns into August."

In the contested district of Zhari, where the government has far less control than in Kandahar city, Hodges said the timing of the beginning of combat operations will depend on when the Afghans are ready to take the lead in governing. American military forces could clear these areas quickly and decisively, he said, but doing so without establishing local governance and permanent security forces would have negative consequences.

"All that would accomplish is a lot of casualties, ours as well as Afghans," he said, "and we would create even more insurgents because we'd be leaving."

Experience in neighboring Helmand province has proved how difficult it can be to establish an effective government presence after clearing a militant stronghold.

Officials on Wednesday confirmed that the government representative in the troubled southern district of Marjah had been replaced, barely six months after a major NATO military offensive to retake the area from the Taliban.

Provincial spokesman Daoud Ahmadi said Abdul Zahir has been replaced as district chief as part of a "reform procedure." He would not say if Zahir was removed because of continued instability in Marjah. The southern farming town -- much like the current Kandahar push -- was intended to be a showcase of good Afghan governance after combined Afghan and international forces expelled the Taliban, but authorities have struggled to consolidate their control.

Hodges, the American commander, said Zahir was ousted for refusing to take a qualification test required under Afghan law. He said he did not have details but suspected the test requirement was waived when Zahir was first recruited as district chief.

Nine Afghan civilians died in Marjah on Tuesday when their vehicle hit a roadside bomb, the Ministry of Interior said. Another homemade bomb killed two security guards traveling on a road in eastern Paktika province.

On Tuesday in Helmand, Britain's forces suffered a blow when an Afghan soldier partnered with them turned against his unit, killing three British troops, including the company commander, before fleeing. The Taliban later announced the man had surrendered to the insurgents and was in "a safe place."

Afghan Gen. Ghulam Farook Parwani identified the soldier Wednesday as Talib Hussein, age 22 or 23, a Hazara minority Shiite Muslim from the eastern province of Ghazni.

The soldier's identity deepened the mystery of his motive, since the Hazara were persecuted by the Taliban when the hard-liners ruled Afghanistan during 1996-2001 with their extreme interpretation of Islamic law. Taliban are mostly of ethnic Pashtun Sunni Muslims who see Shiites as doctrinally impure.

Parwani said Hussein was recruited into the Afghan army only about eight or nine months previously. He said initial investigations indicate Hussein was a habitual hashish smoker.