(CNN) -- In Afghanistan's historic presidential election, former Foreign Minister Abdullah Abdullah is leading the early returns from last week's voting, the country's Independent Election Commission chairman said Sunday.
Abdullah has 41.9% of the vote, according to Ahmad Yousuf Nuristani, who cautioned that it was too early to tell if a single candidate would get the majority of the vote needed to win the presidency without a runoff.
Former Finance Minister Ashraf Ghani was second with 37.6% of the vote, officials said.
Ballots are being hand-counted across the nation, and results will take time to tally.
About 7 million Afghans voted in the elections on April 5, in the country's first democratic transfer of presidential power, choosing a successor to outgoing President Hamid Karzai. He is constitutionally required to step down.
A large number of Afghans turned out last week, in the third election since the fall of the Taliban in 2001. Voter registration started almost a year ago and 2.5 million names were added to the electoral roll. According to the election commission, polling hours were extended to allow everyone in line to vote.
"Today I came here to select my next president and I hope whoever it is ... is a good person, who will help the people and bring changes to Afghanistan," a voter at a polling station told CNN.
Another, in Kabul, said the president must secure the war-torn nation.
"We need a good president so the bombings and war stops," the voter said. "I want my children to go to school without fear."
While Afghans cast their ballots, there was heavy security in the capital, Kabul, and throughout the nation. The Taliban had threatened to disrupt the process and punish all involved in the election.
About 20 people were killed in violence across the country on Election Day, Afghan Interior Minister Mohammad Umer Daudzai told reporters, and at least 43 people were wounded in attacks targeting voting centers. Most of the wounded, he said, were civilians.
Abdullah told CNN's Christiane Amanpour in February that if he won the presidency, he would sign an agreement to keep international forces in Afghanistan and aid dollars coming into the nation.
NATO troops are scheduled to draw down from Afghanistan by the end of the year.
Karzai has refused to sign the bilateral agreement, also known as the Status of Forces Agreement.
CNN's Anna Coren, Masoud Popalzai and Qadir Sediqi contributed to this report.