Afghan security officials secure the road leading to the Interior Ministry after a suicide bomb attack in Kabul on Wednesday. (S. Sabawoon/European Pressphoto Agency)

A suicide bomber attacked the Afghan Interior Ministry on Wednesday, killing six police officers.

The incident comes three days before the country’s presidential election, as the Taliban attempts to carry out high-profile attacks to deter voters and delegitimize the pivotal vote.

In Wednesday’s assault, a man wearing an Afghan police uniform arrived in a black car with tinted windows and approached the officers guarding a ministry checkpoint, said Mohammad Abdul Zahir, Kabul’s police chief. He then detonated his explosive vest, killing six officers and wounding several others. No civilians were injured.

Afghan police have heightened security across Kabul, in some cases forcing restaurants and guesthouses to close to minimize the number of potential targets. In recent weeks, insurgents have hit high-profile hotels, compounds of nongovernmental organizations and the Afghan election commission’s headquarters. The Taliban appears most interested in attacking Kabul, where millions are expected to vote Saturday and where the top candidates will be campaigning.

But as Wednesday’s attack proved, the men protecting Afghanistan’s key ministries are relatively easy targets, clustered around exposed checkpoints. Insurgents have fairly easy access to police uniforms, giving them greater freedom of movement than they would otherwise have.

Most Afghans say the slew of attacks will not deter them from voting, but many here remain worried about the prospect of escalating violence in the coming days.

Mohammad Sharif contributed to this report.

The Afghan presidential campaign has narrowed to a field of eight men, who are running to succeed Hamid Karzai.