Donald Trump's campaign manager Kellyanne Conway said that although the businessman was lagging behind, the Republican campaign hoped he could still win over undecided voters.

"We are behind," Conway said in an interview with broadcaster NBC, adding that Democrat rival Hillary Clinton had "tremendous advantages," including a large campaign war chest allowing her to spend millions on advertising.

An ABC News poll released Sunday gave Clinton a lead of 12 percentage points over Trump - 50 percent to 38 percent - among likely voters. She is also ahead in several crucial battleground states, including Pennsylvania and Florida. Despite the numbers, Conway said Trump had huge support among the American public.

"We're not giving up. We know we can win this," she told Fox News. "The fact is that this race is not over."

Clinton's campaign manager Robby Mook agreed that nothing was decided: "We're not taking anything for granted at all," he told Fox News Sunday. "You know, this is not over yet."

Campaigning in key states

Polls predict a tight race in Florida, which Trump must win in the November 8 election if he's to have a chance of becoming president.

At a rally in Naples, Florida, on Sunday evening, Trump - who is trailing Clinton by a significant margin with Hispanic voters - accused the Obama administration of "abandoning our friends" in Latin America and delivering "only poverty and joblessness for Hispanic Americans right here at home."

Clinton's running mate Tim Kaine, who speaks Spanish, was also campaigning in Florida on Sunday. One of her most powerful surrogates, President Barack Obama, also made a campaign stop in the tightly contested state of Nevada.

Trump: 'Rigged' election

Clinton, meanwhile, visited the cities of Durham, Raleigh and Charlotte in swing state North Carolina. She started the day at a mainly black church, where she called for awareness of  "systemic racism" across the country. She also encouraged voters to cast their ballots early, and took aim at Trump over his recent claims the election is being "rigged" against him.

"He refused to say that he would respect the results of this election, and that is a threat to democracy," she said. "The peaceful transition of power is one of the things that makes America America."

Trump has said he will only accept the election outcome "if I win" - a position that challenges a key cornerstone of American democracy. But on Sunday, Trump's son Eric said the businessman would "100 percent" accept the results of the election if the outcome is "fair."

"I think what my father is saying is, 'I want a fair election,'" Eric Trump told broadcaster ABC. "If it's a fair outcome, he will absolutely accept it. There's no question about that."

AT&T deal

As the presidential candidates were busy campaigning Sunday, both Republicans and Democrats voiced skepticism over a proposed $85.4 billion (78.1 billion euros) takeover of Time Warner Inc by AT&T, announced on Saturday.

Clinton's spokesman said regulators should closely scrutinize the attempt to create a new telecommunications and media giant, while Kaine said he had concerns about higher costs, fewer choices and worse service.

Trump, who has frequently accused the media of bias against him, said he would block the deal if elected. He said the acquisition of Time Warner, which owns CNN and Warner Bros. film studio, would concentrate too much power in one organization.

The Senate subcommittee on antitrust is expected to hold a hearing on the acquisition in November.

nm/cmk (dpa, AP, AFP, Reuters)