KABUL, Oct. 17 (Xinhua) -- A suicide bomber on Tuesday blew his explosive device next to a police training center in Gardez city, capital of Afghanistan's eastern Paktia province, killing at least 20 people and injuring 160 others, a local official said.

The casualties included policemen and civilians, head of provincial health department in Paktia province Hadayat Hamidi told Xinhua.

However, a member of Paktia provincial council Alam Mir Bahram said that the militants detonated two car bombs next to the police training center and the casualties could be higher than reported.

Police have cordoned off the area and operations are underway to eliminate the attacking insurgents. The number of attackers was six, all equipped with suicide vests and light arms, according to security forces.