Crowds queued up outside voter registration centres in Afghanistan and presidential candidates held large campaign rallies, six days ahead of elections that have been shaken by Taliban attacks.
The vote, which will choose a successor to President Hamid Karzai, comes as US-led foreign troops withdraw after 13 years of fighting the Taliban mainly across the south and east of the country.
One Romanian soldier was killed on Sunday by an improvised explosive device (IED) in the southern province of Zabul, taking the US-led coalition death toll to 3,429 since operations began in 2001.
On Saturday, the Kabul headquarters of the Independent Election Commission (IEC) was attacked when five Taliban fighters occupied a nearby building and unleashed rockets and gunfire towards the fortified compound.
All five attackers were killed by Afghan security forces six hours after the attack began. There were no other casualties.
"Our vote is our responsibility, people want change and we will bring that change through voting," said Abdul Waris Sadat, a 21-year-old student waiting with several hundred people for hours outside a voter registration centre in Kabul.
"The attacks by the Taliban have motivated people to come to this centre, register and vote," he said, according to the AFP news agency.
"This is only answer that they give to the Taliban."
Rassoul Khurami, a 60 year-old shopkeeper, added: "I know my vote counts, and this time even if I get killed I will go and vote, I'm not scared of Taliban threats."
According to the latest IEC figures, nearly 3.7 million new voters have registered for Saturday's presidential and provincial council elections.
Afghan officials, the United Nations and foreign donor nations have struck a defiant note ahead of the vote after recent attacks on IEC centres, Kabul's most prestigious hotel and a guesthouse run by a US-based anti-landmine charity.
"Thousands of people are queuing every day behind IEC offices to get voter cards, showing strength and determination that nothing will stop us," said interior ministry spokesman Sediq Sediqqi.
Former World Bank economist Ashraf Ghani and Karzai loyalist Zalmai Rassoul held rallies in the northwestern province of Herat on Sunday, while Abdullah Abdullah, who came second in the 2009 vote, campaigned in the southern province of Kandahar.
"We will be victorious in this election - not through fraud, but based on the votes of the people," Abdullah told thousands of flag-waving supporters.
"These attacks cannot stop the people of Afghanistan, who want to have the election."
Rassoul is widely seen as Karzai's favoured candidate, and Ghani has drawn big crowds to his rallies, but the two could split the Pashtun ethnic vote while Abdullah retains strong support from non-Pashtun communities.