(CNN) -- Egyptians living abroad began voting at diplomatic missions worldwide Friday in what is considered the nation's first free and fair presidential election in modern history.
Voters in 166 nations have until May 17 to cast their ballots at the nearest consulate or embassy, according to the country's election committee.
There are 586,914 Egyptians living abroad eligible to participate in the elections, said Ahmed Ragheb, the deputy foreign minister.
About half of them live in Saudi Arabia, followed by Kuwait, the United Arab Emirates, Qatar, the United States and Canada.
Some consulates are using new technology to match registered voters' information.
"We are using barcodes on national identification cards to match up with lists we have," the Egyptian ambassador to the United States, Sameh Shokri, said in a statement to Egyptian media.
Twelve candidates are running in the presidential election, for which voting in Egypt will be held on May 23 and May 24. One candidate, who was officially listed, recently withdrew from the race.
This week, two of the main candidates met in a debate the first time in the country's history.
Moderate Abdelmonen Abol Fotoh and former Arab League chief Amre Moussa faced off, keeping millions nationwide glued to their TV screens for more than three hours.
"It was really exciting to see the debate. It only confirmed my thoughts that Amre Moussa is the one to vote for," said Ahmed Tayyeb, an Egyptian living in Atlanta.
Others wondered whether the former foreign affairs' minister is too close to the past regime.
"But he is associated with the Mubarak regime!" said Salim Karama, a supporter of Abol Fotoh who was watching the debate with Tayyeb late Thursday. "We need someone to unify Egyptians after so much division."
Protests erupted in Cairo earlier this month amid a backdrop of frustration about the pace of reform since Hosni Mubarak was ousted as president last year. There is concern that Egypt's military leadership is delaying the transition to civilian rule. More than a dozen people were killed in clashes between protesters and security forces in Cairo's central Abbasiya district, prompting authorities to impose an overnight curfew in an effort to restore order. An official military source announced Friday that the curfew would be lifted, state media reported.
If runoff elections are needed, Egyptians living abroad would cast their ballots in a second round of voting between June 3 and June 9, according to the election committee.