Kabul, Afghanistan ? A wave of attacks killed six U.S. troops and at least a dozen civilians Saturday in Afghanistan’s volatile south and east, as American reinforcements moving into Taliban-dominated areas face up to the fierce resistance they expected.

Increased U.S.-led military operations in the southern province of Kandahar are aimed at trying to break the Taliban’s grip where they are strongest by delivering security and government services to win over Afghan people.

The hope is that once the tide begins to turn, more control can be handed to Afghan forces without fear that the Taliban might again seize power, bring back its harsh interpretation of Islamic law and resume sheltering al-Qaida terrorist leaders. Then U.S. troops could begin withdrawing in July 2011, in line with a timeline set by President Barack Obama.

Senior U.S. military officers have warned, however, that the fight in the Taliban’s spiritual birthplace would lead to a rise in casualties for troops. June was the deadliest month of the nearly 9-year-old war, and July has kept pace.

On Saturday, two of the U.S. troops killed died in the south in separate roadside bombings. In Kandahar city, a remote-controlled bomb on a motorcycle exploded, setting cars ablaze and shattering windows at a popular shopping center. The provincial government said one passer-by was killed.

The other American service members died in the east: One as a result of small-arms fire, another by a roadside bomb, a third during an insurgent attack and the last in an accidental explosion. Their deaths raised to 23 the number of American troops killed so far this month. Last month, 103 international troops were killed, 60 of them Americans.

In the spring, as NATO began stepping up patrols in the south, Adm. Mike Mullen, head of the Joint Chiefs of Staff, warned reporters again that such a rise casualties would be inevitable.