Reports from Afghanistan say an explosion rocked the capital, Kabul, early Saturday just hours before polling stations were to open for a parliamentary election.
The French News Agency says the cause of the pre-dawn blast is not known, but the Associated Press quotes a police officer (Abdul Manan) as saying it was caused by a rocket. There was no word about casualties.
The Taliban threatened violence to disrupt the election. Late Friday, NATO said Afghan and coalition forces recovered election ballots from an Independent Election Commission vehicle damaged by a roadside bomb in northwestern Herat province, while four NATO troops were killed across the country.
The Taliban claimed responsibility for abducting at least 19 people, including a candidate, eight election officials and 10 campaign workers.
U.S. officials said they expect Afghanistan's parliamentary elections to be successful. White House spokesman Robert Gibbs said Friday the insurgents feel threatened by the elections and will do anything to undermine them.
Afghan President Hamid Karzai urged all Afghans to vote.
The streets of Kabul were mostly quiet Friday, as police set up additional checkpoints and searched cars traveling on the main roads.
The Afghan Defense Ministry said nearly 300,000 Afghan police and soldiers, backed by 150,000 international troops, will provide security during the election.
Even so, election officials have said roughly 15 percent of more than 6,000 polling centers will not open due to security concerns.
After voting closes Saturday, polling officials are expected to compile their station's results and send the result sheets and votes to a tally center in Kabul.
Preliminary results are not expected before October 8. Final results likely will be announced at the end of next month, following the resolution of any complaints of fraud or misconduct.
Some information for this report provided by AP and AFP.