KABUL, Afghanistan -- A Taliban suicide bomber managed to get past a security checkpoint Wednesday and then blew himself up at the entrance to the Afghan Interior Ministry, killing six police officers on the last day of campaigning in this country's closely watched presidential election.
The midafternoon bombing outside one of Kabul's most heavily guarded government installations was the latest of several major attacks that have sown fear in the Afghan capital ahead of Saturday's contest that will determine President Hamid Karzai's successor.
Interior Ministry spokesman Sediq Sediqqi said the bomber got through at least one checkpoint on foot and then detonated his explosives near a reception area where police officers and visitors regularly pass in and out of the complex. Four other police officers reportedly were injured.
The Interior Ministry initially said the bomber was wearing a military uniform, but Sediqqi said that information was unconfirmed.
The Taliban claimed responsibility for the attack moments after it occurred.
Kabul's normally traffic-clogged streets were subdued at dusk. Uniformed security personnel were stopping cars for inspections, and some residents reported that police were encouraging them to stay at home over the next couple of days, apparently due to concerns about further violence.
Shortly before the Interior Ministry blast, a Taliban spokesman issued a statement warning of more attacks aimed at derailing the election, which the insurgent group has described as a foreign plot.
Afghan officials are pressing ahead, however, and forecasting solid voter turnout based on long lines of people who sought to collect voter registration cards in recent days. Ballots and other election materials have been distributed to all 34 provinces and will arrive at polling centers, sometimes by donkey cart, by Friday evening, officials said.
"Maybe some insurgent groups want to sabotage the election, but the people of Afghanistan are keen to participate in deciding the future of their country," Noor Mohammed Noor, spokesman for Afghanistan's Independent Election Commission, said in an interview Wednesday.
As Noor spoke, however, security personnel outside his office were busily erecting new concrete barriers along the perimeter of the election commission headquarters, which was attacked last week by insurgents who infiltrated a house a few hundred yards from the gate.
Election officials have announced that about 750 of more than 7,000 polling centers nationwide would not open due to security fears or the inability of Afghan soldiers and police to secure the locations.
The leading presidential candidates -- former Finance Minister Ashraf Ghani, former Foreign Minister Zalmai Rasoul and 2009 presidential runner-up Abdullah Abdullah -- held their final campaign events Wednesday at locations around Kabul. Under Afghan law, there is to be no more campaigning until polls open Saturday morning.