Washington - Americans headed to the polls Tuesday in a historic presidential election as Republican John McCain and Democrat Barack Obama made a final push for votes in key battleground states.

McCain campaigned in Colorado where he claimed he had regained momentum and expressed confidence that he would defeat Obama when all the ballots are counted.

Chicago - Lines had formed by midday outside Chicago's Grant Park, where up to a million people are expected to gather to witness Illinois Senator Barack Obama's post-election rally late Tuesday.

Chicago residents Nick Boten, 37, and Scott Larson, 38, joined the line at around 12:30 pm, eight hours before organizers would let them into the park - and they weren't even near the front of the line, which got longer and longer through the course of the afternoon.

Washington - Republican presidential candidate John McCain said Tuesday he has regained momentum and expressed confidence that he would overtake Democrat Barack Obama when all the ballots are counted.

"I feel momentum," McCain said in one of his final rallies in Grand Junction, Colorado, before polling stations close Tuesday evening. "We are going to win this election, we are going to win it right here in Colorado."

Pristina - The United States will continue to take part in the international peacekeeping mission in Kosovo regardless of the outcome of its presidential election, NATO Secretary General Jaap de Hoop Scheffer said on Tuesday.

"Regardless who the winner of the elections will be, I don't expect any change regarding United States policy towards Afghanistan and Kosovo," he said in Pristina after meeting with Kosovo officials.

Rockville, Maryland - Democratic presidential candidate Barack Obama barely bothered to campaign in Maryland, a traditional Democratic stronghold.

On Tuesday, voters came out in droves to wait hours outdoors in mild autumn temperatures to participate in the historic election that could produce the first African American president in US history.

Washington - As Republican presidential candidate John McCain arrived at the Albright United Methodist Church in Phoenix, Arizona Tuesday to vote, scores of supporters cheered: "Go, John, go."

McCain was with his wife Cindy. In a break from tradition, he planned two final rallies on voting day - at an airplane hangar in Grand Junction, Colorado and later in Albuquerque, New Mexico. Both states went with President George W Bush in 2004, but polls have indicated that they are now leaning toward Obama.