A bomb exploded near a U.S. military patrol in southern Afghanistan (search) on Saturday, killing one American soldier and wounding three others, the military said.

The attack occurred as the troops were traveling in an armored vehicle in Zabul province's Shinkay district, U.S. military spokesman Lt. Col. Jerry O'Hara said.

A purported Taliban spokesman, Mullah Latif Hakimi, claimed responsibility for the attack in a telephone call to The Associated Press. His claim could not be verified.

The death brings to 144 the number of U.S. troops killed in and around Afghanistan since Operation Enduring Freedom began in 2001.

Two of the wounded soldiers were taken to a U.S.-led coalition base near the town of Qalat for treatment, a military statement said. The third was taken to a base near the southern city of Kandahar and was expected to be flown to Landstuhl, Germany, for further treatment. The soldiers' names were not released.

"There will be considerable efforts made to find out who is behind these attacks and prevent more like it," O'Hara said. "This incident will not prevent us from accomplishing our mission."

After a winter lull, loyalists to the ousted Taliban regime and other militants opposed to the U.S.-backed government of President Hamid Karzai have ramped up their insurgency with a series of bombings and other attacks.