July 2 (Bloomberg) -- Thousands of U.S. Marines began a “major operation” in southern Afghanistan early today, moving into towns and villages to protect civilians from the Taliban under the Pentagon’s new counterinsurgency strategy.

Almost 4,000 American personnel and 650 Afghan soldiers are taking part in Operation Khanjar, or Strike of the Sword, pushing into the Helmand River valley in helicopters and armored vehicles to set up bases, the military said in an e-mailed statement.

“Where we go, we will stay and where we stay, we will hold,” Brigadier General Larry Nicholson said in the statement.

The operation comes two days after U.S. combat troops withdrew from Iraqi cities under a drawdown that will allow the Pentagon to focus on the conflict in Afghanistan. The Marines involved in today’s offensive were deployed as reinforcements in May, as part of President Barack Obama’s commitment to defeat a resurgent Taliban.

U.S. General Stanley McChrystal assumed command of international forces in Afghanistan last month and is spearheading new counterinsurgency tactics aimed at better protecting civilians.

U.S. and NATO-led forces have failed to establish a permanent presence in the Helmand River valley, an insurgent stronghold and center of illicit opium production where militants have thrown out local police and government officials.

Gaining Trust

McChrystal has said troops must focus on gaining the trust of the people to win the conflict and told the Wall Street Journal last month he will push soldiers farther out from their bases among Afghan civilians to try to bring stability.

“The measure of effectiveness will not be the number of enemy killed, it will be the number of Afghans shielded from violence,” the general said in a statement last month.

The operation aims to “connect local civilians with their legitimate government” and bring secure conditions for national elections scheduled for August, according to the statement.

Troops will “build bases to provide security for the local people,” Helmand Governor Gulab Mangal said in the statement.

The U.S. has about 54,000 soldiers in Afghanistan, with 36,000 in NATO’s International Security Assistance Force and 18,000 in a separate counterterrorism operation.

The number of U.S. soldiers in the country is set to rise to 68,000 this year as part of Obama’s plan to shift resources from Iraq.

The reinforcements should enable the U.S. to follow a “classic counterinsurgency strategy of clear, hold and build,” something troops have failed to do since toppling the Taliban regime in late 2001, said Anthony Bubalo, director of the West Asia Program at the Sydney-based Lowy Institute.

“If you cannot hold territory and provide security, you can’t undertake the kind of development work you need to do to win hearts and minds and strengthen the authority of the government in Kabul,” he said.

To contact the reporter on this story: Ed Johnson in Sydney at ejohnson28@bloomberg.net.

Last Updated: July 1, 2009 21:39 EDT