The US state of Ohio remained in campaigning mode Tuesday as the two camps made last-minute efforts to win this crucial battleground in the ongoing presidential election.

Vice President Joe Biden landed in the Ohio city of Cleveland on an unannounced visit after Republican presidential candidate Mitt Romney had arrived for a scheduled stop.

Shortly after Biden's arrival, Romney's running mate, Paul Ryan, flew in to join Romney in a last-minute push in the Midwestern industrial state, which has chosen the winner of the last 12 presidential elections.

The vice president visited a local restaurant with his family, taking photos and chatting with voters, according to the website of The Washington Post.

Biden voted on Tuesday morning in his home state of Delaware, and is expected to join President Barack Obama in Chicago to wait for the final election outcome.

In hometown Chicago, Obama, who had cast his ballot in early voting, met with volunteers to thank for their work, saying he expects to have "a good night" by the end of the Election Day.

He also congratulated Romney on a "spirited campaign" and expressed his confidence to secure reelection. "We feel confident we've got the votes to win," he told reporters.

While Obama became the first sitting president to take advantage of early voting operations last month, Romney voted early Tuesday in Belmont, Massachusetts, the state where he once served as governor.

Also on Tuesday, Obama's grandmother, Sarah Obama, expressed confidence that her grandson will be re-elected.

Speaking in her Kenyan village of K'Ogello, where local residents are following closely the ongoing voting in United States, Sarah heaped praise on her grandson, saying his unique leadership style of uniting all the races is a key factor for his reelection bid.

"His style of leadership skills which he has used to unite all the races in the US is the reason why he is liked by many," said the 90-year-old granny.

Meanwhile, the more than 12 million Hispanic American voters,

including Mexican Americans, Puerto Ricans and Cuban Americans, are also a key element to determine who is the next US president.

According to the US Census, Hispanics now make up about 16 percent of the entire US population, and their choices are rather important in such swing states as Nevada, Colorado, Florida and Virginia, all of which have sizeable Hispanic constituencies.

In a recent poll conducted by Hispanic media group ImpreMedia and pollster LatinoDecisions, 73 percent of the registered Hispanic voters would support Obama, while 24 percent are for Romney.