Some 4,500 U.S. citizens living in Yucatan Peninsula, east of Mexico, have already cast ballots ahead of the U.S. presidential election day on Nov. 4, U.S. consul in Mexico Karen C. Martin said on Sunday.

During a press conference in the city of Merida, capital of Yucatan, Martin said that the U.S. citizens voted according to the electoral system of their origin-state.

The amount is calculated based on the U.S. records of the citizens living in the sates of Yucatan, Campeche and Quintana Roo, which form the Yucatan Peninsula in the Mexican Caribbean.

On Nov. 4, U.S. citizens over 18 will vote to choose a new president between Democratic candidate Barack Obama and Republican candidate John McCain.

(Xinhua News Agency November 3, 2008)