One week before election day, public opinion polls show the U.S. presidential race tied not only at the national level, but in several key states.
Republican President Bush and his Democratic challenger John Kerry have been running virtually even in Ohio, Florida, Pennsylvania, and about six other contested states.
Analysts say these states will determine which candidate wins a majority of "electoral votes," which ultimately decide the presidency.
A candidate wins electoral votes by taking a majority of individual votes in a state. The electoral votes are proportional to the state's population.
The most hotly-contested state has been Florida, which has 27 electoral votes - one-tenth of the 270 needed for a majority.
Analysts say other "battleground", or close-race states still up for grabs include Iowa, Colorado, Wisconsin, Minnesota, Nevada, and New Mexico.
Some information for this report provided by AFP.