South Koreans in the United States began casting their ballots Wednesday in the presidential election in their homeland.

It is the first time that South Koreans abroad have taken part in presidential polls, thanks to a revised election law that took effect in 2009.

The early voting is taking place at a dozen polling stations across the United States, including one in the Virginia suburbs of Washington, according to officials at the South Korean Embassy.

The election, slated for Dec. 19, pits Park Geun-hye of the conservative ruling party and Moon Jae-in of the liberal opposition camp in a tight, two-way race.

"There are around 866,000 South Koreans in the U.S. eligible for the voting," said Jung Tae-hee, in charge of election issues at the South Korean Embassy in Washington.

"The registration rate is at the level of 6-7 percent," he added, meaning about 72,000 people will be able to vote.

South Korean Ambassador to the U.S. Choi Young-jin visted a polling site in northern Virginia for balloting.

South Koreans in other nations also started casting their ballots.

More than 110,000 people are expected to vote in Asia and 23,000 in Europe.

Voting will take place for four to six days, depending on region.

South Koreans living in foreign countries gained their voting rights in presidential and general elections after the National Assembly passed a bill to grant suffrage to them in 2009.

The move came in response to a 2007 ruling by the Constitutional Court that recognized overseas citizens' rights to vote in their homeland's elections. (Yonhap News)