KABUL, Oct 8 (AFP) - A large explosion was heard in Afghanistan's capital in the early hours of Friday ahead of presidential elections on Saturday, officials said.
A spokesman for NATO peacekeepers, Ken McKillop, told AFP that the troops had heard the blast at around 0130 am (2100 GMT Thursday).
Another NATO spokesman, Valery Putz, said the explosion appeared to be near the peacekeepers' headquarters in Kabul.
A Western security source told AFP the blast was near a media accreditation centre for the elections close to the German embassy.
Several embassies, the NATO international security force headquarters, and the United Nations compound are in the same area of the city.
Reporters trying to reach the scene found the roads blocked by Afghan police and US soldiers.
"The nature of the explosion is unknown at this stage. It could be a rocket or something else," the security source said.
Afghans vote on Saturday in elections which militants of the former Taliban regime have vowed to disrupt.
The Taliban were ousted by a US-led invasion which began three years ago on October 7, when they refused to hand over Al-Qadea leader Osama bin Laden after the September 11 terror attacks on the United States.
More than 18,000 US troops are still in the country, backed by some 9,000 NATO troops.
US-backed President Hamid Karzai is widely expected to win the election against 17 other candidates.