Some U.S. and Afghan troops say they are fighting the latest offensive in southern Afghanistan with a handicap -- strict rules that routinely force them to hold their fire.

Although details of the new guidelines are classified to keep insurgents from reading them, U.S. troops say Taliban fighters are keenly aware of the restrictions.

"I understand the reason behind it, but it's so hard to fight a war like this," said Lance Cpl. Travis Anderson, 20, of Altoona, Iowa. "They're using our rules of engagement against us."

Must have a weapon

If a man emerges from a Taliban hideout after shooting erupts, U.S. troops say they cannot fire at him if he is not seen carrying a weapon -- or if they did not personally watch him drop one.

What this means, some contend, is that a militant can fire at them, then set aside his weapon and walk freely out of a compound, possibly toward a weapons cache in another location. It was unclear how often this has happened.

Anderson said his platoon had repeatedly seen men drop their guns into ditches and walk away to blend in with civilians.

Airstrikes hampered

In another example, Marines pinned down by a barrage of insurgent bullets say they cannot count on quick air support because it takes time to positively identify shooters.

"This is difficult," Lance Cpl. Michael Andrejczuk, 20, of Knoxville, Tenn., said Monday. "We are trained, like, when we see something, we obliterate it. But here, we have to see them, and when we do, they don't have guns."

The commanders' rationale

NATO and Afghan military officials say killing militants is not the goal of a 3-day-old offensive to take control of the Taliban stronghold of Marjah in southern Afghanistan. More important is to win public support.

They acknowledge the rules entail risk to the troops but maintain that civilian casualties or destruction of property can alienate the population and lead to more insurgent recruits, more homemade bombs and a prolonged conflict.

Under the current rules of engagement, though, troops retain the right to use lethal force in self- defense, said U.S. Col. Wayne Shanks, a spokesman for the international force.

Not like Iraq

The approach is a marked change from the battle for the Iraqi town of Fallujah in November 2004. When Marines there encountered snipers holed up in a building, they routinely called in airstrikes. In Marjah, fighter jets are flying at low altitude in a show of force but are not firing missiles.

Civilians at risk

Politically, it's not the best time to campaign for relaxing the rules in Afghanistan. On Sunday, two U.S. rockets struck a house and killed 12 Afghan civilians during the offensive in Marjah, NATO said. On Monday, a NATO airstrike accidentally killed five civilians and wounded two in neighboring Kandahar Province.

It was public outrage in Afghanistan over civilian deaths that prompted the top NATO commander, U.S. Gen. Stanley McChrystal, last year to tighten the rules, including the use of airstrikes, if civilians are at risk.

Questions for troops

The rules seek to put the troops in the "right frame of mind to exercise that right," Shanks said. They require troops to ask a few fundamental questions:

•Even if someone has shot in my general direction, am I still in danger?

•Will I make more enemies than I'll kill by destroying property or harming innocent civilians?

•What are my other options to resolve this without escalating the violence?