An Afghan policemen at the blast site in Kabul.
An explosion occurred near the Supreme Court in the centre of Afghanistan's capital, Kabul, killing at least 20 people, government officials said.
The Ministry of Public Health said at least 20 people were killed and 38 injured people were taken to city hospitals, in what appeared to be the latest in a series of attacks on the judiciary.
There was no immediate claim of responsibility for the attack, in which police said an apparent suicide bomber targeted Supreme Court employees leaving their offices at the end of the working day.
Last month, Taliban bombers killed more than 30 people and wounded about 70 in twin blasts in a crowded area of the city during the afternoon rush hour.
The Taliban is fighting to oust foreign forces and bring down the US-backed government, claimed responsibility for the January 10 attack.
Afghan government forces control no more than two-thirds of national territory, and have struggled to contain the Taliban insurgency since the bulk of NATO soldiers withdrew at the end of 2014.
Several thousand foreign troops, most of them Americans, remain in training and counter-terrorism roles.