At least 20 people have been killed or injured in a suicide bomb attack in Afghanistan's western Herat province, reports say.

阿富汗西部赫拉特省发生自杀式炸弹袭击，死伤人数至少20人。

The attack targeted the government headquarters of Guzara district as people queued to see officials, AP quoted a local official as saying.

Eyewitnesses¹ saw shattered bodies and mangled² metal after the blast.

The suicide bomber³ apparently⁴ drove up in a four-wheel-drive vehicle before detonating a cache（隐藏处） of explosives.

"When a suicide bomber tried to enter the district headquarters, he was stopped by the police but then he detonated his explosives - right at the gate," district head Nasar Ahmad Popul, who was inside the building at the time of the blast, told the AP news agency.

Mr Popul said police and civilians⁵ were among those wounded.