Officials say a suicide blast has hit the Afghan Interior Ministry compound in Kabul, the latest violence in Afghanistan in the run-up to Saturday's elections.
The ministry said a bomber wearing a military uniform detonated his explosives at the main gate Tuesday, killing at least four police officers.
The Taliban has repeatedly vowed to disrupt the presidential and provincial council elections and warned voters to stay away from the polls.
Elsewhere in Afghanistan, authorities said Tuesday that militants have killed nine people in northern Sar-e-Pol province, including a politician kidnapped earlier this week.
Hussain Nazari was a candidate for the provincial council in northern Afghanistan.
The eight other victims have not been identified.
No one has claimed responsibility for the killings, but authorities blame the Taliban.