KANDAHAR, Afghanistan - Afghan police clashed with suspected Taliban militants in southern Afghanistan Wednesday, killings three fighters and detaining four, a police official said.

The militants were killed and captured between the provinces of Kandahar and Uruzgan, where nine border policemen were killed in a militant ambush on Tuesday, said Matiullah Khan, an officer with border police.

Afghan and NATO-led forces also battled suspected militants for nearly five hours in Uruzgan province on Tuesday, leaving 12 Taliban and nine policemen dead, Uruzgan's police chief, Gen. Mohammad Qasem, said. Four militants and 10 Afghan troops also were wounded, he said.

The southern clashes came after a suicide bomber blew himself up in a crowd of labourers outside a U.S. military base in eastern Afghanistan on Tuesday, killing as many as 10 people in the deadliest suicide attack in four months.

The suicide bomber struck as hundreds of Afghan workers lined up to enter the base, known as Camp Salerno, outside the city of Khost, said provincial Gov. Jamal Arsalah, who visited the scene shortly after the explosion.

Meanwhile, Gulbuddin Hekmatyar, an Afghan warlord whose fighters operate in eastern Afghanistan's mountains alongside the Taliban and al-Qaida, said the U.S. faces a Soviet-style humiliation in the country.

In a recording obtained by The Associated Press in Pakistan, Hekmatyar also accused Washington of fomenting conflict among Afghan ethnic groups on a scale comparable with the strife in Iraq.

"Everyone knows that the American aggressors are faced with defeat in every part of the country,'' Hekmatyar said. "They were unable to achieve their goals by bombing innocent Afghans, their villages and homes. They are preparing to leave like the Soviet troops.''

The 24-minute recording, the third from Hekmatyar to surface this month, was undated. It was unclear where it was recorded.