A suicide attacker in a police uniform killed 19 policemen Monday after infiltrating their morning exercises in Afghanistan`s province of Uruzgan, authorities said, according to AFP.

Interior ministry spokesman Zemarai Bashary said the bomber infiltrated a police reserve unit in the provincial capital Tirin Kot at 9:30 am (0500 GMT) and detonated explosives strapped to his body.

"Nineteen policemen were martyred and another eight are wounded," he added. Police had earlier said 18 policemen were killed in the blast.

Juma Gul Himat, the provincial police chief, said the number of wounded may rise but that eight, some of them in a critical condition, had been registered so far.

Himat said the attacker was not a policeman but had acquired a uniform and merged into the crowd.

"We have launched an investigation into the incident," he added.

A Taliban spokesman, Yousuf Ahmadi, claimed responsibility for the blast in a telephone call to AFP.

"We claim responsibility for the suicide attack in Tirin Kot," he said. "We will provide you with more information later on the casualties."

Uruzgan is one of four provinces in southern Afghanistan badly hit by an increasingly deadly insurgency since the 2001 US-led invasion ousted Taliban militants from power and implanted a Western-backed government.

Taliban Islamist fighters frequently carry out suicide attacks and roadside bomb blasts against NATO forces, US-led troops, Afghan police and army.

On Sunday, a suicide attacker detonated a car bomb near a convoy of foreign troops on the outskirts of the capital, Kabul, wounding three people including one soldier.