HELMAND, Afghanistan — A smart bomb has been used to destroy something that costs more than a smart bomb for the first time since the introduction of precision-guided munitions in 1968, sources confirmed today.

U.S. forces employed Hellfire laser-guided missiles to destroy five Taliban gun trucks as they prepared to attack Musa Qala, a district center in Helmand Province, Afghanistan.

"We assess the value of these trucks that we destroyed as being about $200,000 a pop," Gen. Austin S. Miller, commander of NATO forces in Afghanistan, told reporters. "A Hellfire missile only costs $115,000. This was the most efficient strike we've seen in this war yet.

The White House said the strike is proof the administration's strategy in Afghanistan is working.

"This is what winning looks like. It's proof that we're putting the Taliban in a place where they be forced to negotiate," said a senior administration official, who was not authorized to speak publicly. "They can't afford this."

Some Pentagon officials have pushed back on this assessment.

"The armored Humvees that the Taliban had stolen from the Afghan National Army originally cost $220,000, and we paid the Afghan interior ministry $8,300 in bribes to get them into the country," John Sopko, the special inspector general for Afghanistan reconstruction, told reporters. "Also, the Taliban were using these as substitutes for trucks that they buy for $800 in Peshawar. So the general's assessment of the replacement cost of these vehicles is not accurate."

Foreign policy experts have raised concerns the White House could be overstating the long-term effects of the strike.

"This will not have a significant impact on the outcome of the conflict," noted John Gentle, a foreign policy expert at RAND Corporation. "The U.S. spends $167 million a day in Afghanistan, and the American people don't even know we're still there. I don't think they really expect our forces there to be efficient at this point. What is an efficient war, anyway?"

Samuel X. Clemens of No Such Agency contributed to this report.