Voting has closed in nearly all U.S. states in the closely contested election pitting President Barack Obama against Republican challenger Mitt Romney.
The first projected results have Obama, a Democrat, winning 148 electoral votes and Romney with 174 Electoral College votes.
The projections say Obama won in the battleground states of New Hampshire and Pennsylvania. Romney won in 19 states, including Indiana, which went for Obama last election. The battleground states of Florida, North Carolina, Ohio and Virginia are too close to call.
The candidates made a final push for support Tuesday as voters waited in long lines at polling places. Some sporadic problems were reported, and both candidates dispatched lawyers to monitor the voting for any irregularities.
Polls remained open to allow people still in line at closing time to cast ballots.
The Justice Department has nearly 800 observers in 23 states to respond to any allegations of fraud.
Related story by Chris Simkins:
After a year-and-a-half of campaigning, three debates and thousands of televised campaign ads, nationwide pre-election surveys showed the two candidates in a virtual deadlock.
But the surveys also show Obama with a slight edge in a handful of key battleground states that are likely to determine the outcome.
U.S. presidential elections are not decided by the national popular vote, but rather by the Electoral College system, developed more than 200 years ago, in which each of the 50 states' influence on the outcome is roughly equivalent to its population.
A candidate needs at least 270 of the available 538 electoral votes to win the election.
Voters wait in line at a polling place located inside a shopping mall in Austin, Texas.
The first Election Day voter of the morning enters Springhill School in Belgrade, Montana. Springhill School is the polling station for Precinct 17, a place where ranchers, affluent professionals and retirees alike live and vote.
Mitt Romney and wife Ann Romney vote in Belmont, Massachusetts
President Obama calls to thank volunteers in Wisconsin, at a campaign office call center the morning of the 2012 election, in Chicago.
Volunteers for Obama's re-election campaign place phone calls to voters and other volunteers at a field office on the south side of Chicago on election day.
Poll workers helps voters in a dark and unheated tent serving as a polling site on Staten Island, New York. The original polling site, a school, was damaged by Superstorm Sandy.
Republican vice presidential candidate Paul Ryan and presidential candidate Mitt Romney leave a campaign plane in Cleveland, Ohio, November 6, 2012.
Voters outside a polling place in Arlington County, Virginia. (Dimitris Manis/VOA)
A sign erected by a community group called Rebuild Rockaway shows voting locations in the Rockaway neighborhoods in Queens, New York.
A voter adjusts a sign as he leaves the home of Vincent Smith in Varnville, South Carolina. The polling place for the U.S. presidential and local elections is located in the den of Smith's home.
Mitt Romney greets campaign workers during a visit to a voter call center in Green Tree, Pennsylvania.
Stickers stating "I Voted" in several languages are affixed to a ballot machine in Los Angeles, California.
Voters wait to cast their ballots in San Juan, Puerto Rico. The U.S. island territory does not get a vote in the U.S. presidential election, but they are voting in a referendum that asks voters if they want to change the relationship to the U.S.
87-year old voter Rolf Kleinwort placed his "I Voted" sticker on the front of his walker as he heads back to his residence at the St. Andrews Estates North retirment community in Boca Raton, Florida.
Villagers dance at an all-night party to watch the U.S. presidential election in the village of Kogelo, home to Sarah Obama the step-grandmother of President Barack Obama, in western Kenya, November 6, 2012.
People try out a mock polling station at a hotel during a US presidential election results event organized by the US embassy in Beijing, November 7, 2012.
Voters also are electing all 435 members of the House of Representatives, and 33 of the 100 members of the Senate. Republicans are projected to continue to hold their majority in the House, while the president's Democratic Party is expected to maintain its slim majority in the Senate.
Millions of Americans already have cast ballots in early voting, in the last month.
Obama voted a few days ago in his home city of Chicago, and spent Tuesday there. He conducted interviews for broadcast in key states and played basketball with friends, one of his Election Day traditions. He also called voters from a campaign office.
Romney, a one-time venture capitalist, voted Tuesday morning in Massachusetts, the northeastern state he once governed but where Obama won. He also made a final push for votes in the key states of Ohio and Pennsylvania.