A suicide bomber attacked Afghanistan's Supreme Court just as staff were leaving work Tuesday, killing at least 20 people and injuring 41 in the second attack on government institutions in under a month.

The bomber, who was on foot, detonated the device in the parking lot as employees were boarding a bus to go home, interior ministry spokesman Najibullah Danish said. The casualty figures came from health ministry spokesman Waheed Majroh, who said women and children were among the wounded.

Police blocked off the road around the compound as panicked relatives of court employees began to gather and ambulances and fire trucks arrived. The compound is sited on the road leading from Kabul international airport to the US embassy.