WASHINGTON - One U.S. troop was killed and two wounded in fighting Tuesday in southern Afghanistan, the U.S. military command in Kabul said.

The fighting, which reflects intensified efforts by the U.S. and its Afghan partners to push back against recent Taliban gains, was near the city of Marja, Helmand province, which shares a border with Pakistan. The Taliban in recent weeks have focused their efforts on retaking parts of Helmand, and the U.S. has countered with U.S. special operations forces working with Afghan troops.

Details on the battle were sketchy.

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CBS News correspondent David Martin reports Pentagon officials told him troops operating with Afghan forces near Marja in Helmand took casualties.

A Medevac was sent into pick up the casualties. While it was on the ground, a mortar went off nearby, possibly damaging one of the rotors. At last report, the Medevac is still on the ground.

In a brief written statement announcing the three U.S. casualties, the U.S. military command in Kabul said one died of wounds sustained "during operations" in Marja, and that two were wounded. The statement did not identify their service branch. Two U.S. officials said they were special operation troops.

"We are deeply saddened by this loss," said Brig. Gen. Wilson A. Shoffner, a spokesman for U.S. forces in Afghanistan. Speaking for Gen. John Campbell, the top U.S. commander in Afghanistan, Shoffner said, "our heartfelt sympathies go out to the families and friends of those involved."

A U.S. helicopter was sent to evacuate the casualties but did not immediately take off because of an unspecified problem.