KABUL, AFGHANISTAN – Militants managed to penetrate one of the safest nooks of Kabul to detonate a massive car bomb Saturday, shaking the confidence of voters just five days before presidential elections.

The powerful blast, for which the Taliban claimed responsibility, killed seven Afghan civilians and wounded 91 more. The bomb went off outside NATO headquarters just after 8:30 Saturday morning, the beginning of the Afghan workweek. It sent a plume of smoke visible around Kabul and knocked out glass windows more than 500 feet away.

The attackers managed to get past at least one police checkpoint to enter a zone that includes the NATO compound and the US Embassy. Insurgents appear to be targeting the capital to create high-profile shocks seen around the country, the aim being to sow doubt about the safety of turning out to vote Thursday.

“No one can guarantee our lives if we take part in the elections,” says Sher Mohammad Faqiri, a driver who works near the scene. His colleague, Noor Sherzai, helped carry three wounded people off the street. “This is the safest area in Kabul. I don’t know if I will attend elections.”

The nation’s security forces have developed a three-tiered strategy for securing approximately 7,000 voting centers on Thursday. The plan is that police will check voters as they enter, while Afghan National Army forces stand as backup. The final backstop will be NATO forces, which will be based some distance away, but close enough to respond rapidly. But it is unclear if each polling station will actually have that level of protection.

While these three forces are supposed to be in close coordination, an incident at Saturday’s blast calls that into question. About an hour after the blast, the police chief charged with securing the elections in Kabul arrived on scene. Gen. Sayed Abdul Ghafar Sayed Zada, whose regular job is as chief of the criminal investigation department with the Kabul police, stepped under a security cordon tape stretched across the scene. An investigator at heart, he first bent down to pick up a small scrap of paper he saw lying on the street and looked it over.

When he rose, he was intercepted by representatives of the International Security Assistance Force (ISAF). He explained who he was, but got the response: “We don’t care who you are; now it’s under control of ISAF.”

“That’s just atrocious COIN [counterinsurgency],” says Tim Lynch, an Afghanistan-based security expert referring to counterinsurgency. “You’ve got a new general here talking COIN. And in the manual they have written themselves, it would absolute mandate close coordination with that guy.”

Mr. Lynch adds that the execution of this car bomb was superior to previous insurgent efforts in Afghanistan.

Across the country, there’s doubt that every voting center will be able to open, given the insecurity. The Free and Fair Election Foundation of Afghanistan estimates that 14 of the country’s 368 districts will be too insecure to send independent election monitors. An additional 130 fall into a questionable category.

Most of these troubled districts lie in the Pashtun-dominated south and east of the country. While Kabul has enjoyed relative security, the city police understand that the Taliban will be targeting it in an effort to undermine the image of the election in the eyes of the world.

Bomb in Kabul targets NATO headquarters, near US Embassy