The Taliban kidnapped an Afghan parliamentary candidate on Friday and another 18 election workers as security forces went on high alert to stop insurgents derailing the nationwide vote at the weekend.
The hardline Islamist militia, which has been fighting an insurgency for nine years since being overthrown from power in the 2001 US-led invasion, has already threatened attacks to disrupt Saturday's poll and called for a boycott.
It claimed responsiblity for snatching Abdul Rahman Hayat, a candidate from eastern Lagman province, on Friday and an electoral official also blamed the other abductions on the Taliban, which has previously killed three candidates.
"We have kidnapped Hayatullah Hayat," Taliban spokesman Zabihullah Mujahid said in a text message to an AFP reporter.
The insurgents were also blamed for the kidnapping late Thursday of 18 electoral officials and campaign workers in northwestern Baghdis province.
The Taliban have threatened to attack polling centres, election workers and security forces, and a spokesman for the insurgents warned that voters who dare to try to cast ballots "will get hurt".
More than 2,500 candidates are standing for 249 seats in the Wolesi Jirga, or lower house of parliament, in the second such vote since the Taliban regime was ousted.
But adding to concerns that the election will be marred by fraud, authorities said they had seized thousands of fake voter cards and observer accreditation badges in Kabul and the provinces of Ghazni and Ghor.
"We have seized thousands of fake cards. Some people have also been detained," an official from the country's National Directorate of Security (NDS) spy agency said, speaking anonymously.
Coming after last year's presidential election, when more than a million votes were cancelled amid massive fraud mostly favouring President Hamid Karzai, many observers are hoping this vote will be better.
Streets were quiet and shops shuttered for the weekly Muslim day off as police manned road blocks set up to keep Taliban militants out of the capital.
Amid the trappings of democracy laid over a traditional, concensus-based society, managing expectations has become a priority for Afghanistan's war-weary Western partners.
The UN envoy to Afghanistan, Staffan de Mistura, on Thursday visited the Taliban heartland of Kandahar, where the insurgency is at its fiercest and the region which military commanders say is key to ending the long war.
"The purpose of my visit was to demonstrate the support of the United Nations for the independent electoral authorities and the people of Afghanistan as they prepare to vote," he said.
Yet thousands of people may not be able to vote with many polling stations, particularly in Taliban strongholds, to remain closed because security cannot be guaranteed.
De Mistura has been vocal among Western diplomats in playing down expectations of corruption and intimidation, saying Afghanistan is not Switzerland and "these elections will not be perfect".
Peter Manikas, of the US-based National Democratic Institute (NDI), said standards should not be compromised simply because Afghanistan is at war.
"I understand that in the context of conflict there are places too dangerous to hold an election but I don't think that means we should be lowering our standards.
"Conflict doesn't excuse massive fraud, and it doesn't excuse not being able to hold the election in every district and they should do everything they can to ensure they can do that," said Manikas, director of NDI's Asia programme."What's important is to evaluate the election as a whole, you can't just look at a snapshot on the day," he told AFP.
US Defence Secretary Robert Gates said a new counter-insurgency strategy appeared to be working and that the NATO commander in Afghanistan, General David Petraeus, believed the war effort was on "the right track".
The United States and NATO have close to 150,000 troops in Afghanistan, many deployed in the south, but 2,000 foreign troops have been killed since the war began.