FLORIDA (REUTERS) - US presidential nominee Donald Trump on Sunday (Oct 23) accused his Democratic rival, Mrs Hillary Clinton, of being "trigger-happy" and said she would start a war in Syria.

Mr Trump told a crowd in Naples, Florida that Mrs Clinton appeared to be weak, but that her appearance was deceiving.

"And you watch her at the end of the debate where she's like exhausted, she could hardly make it to her car," he said, "but she's trigger happy and she wants to start shooting wars in Syria."

Mr Trump has advocated for a "safe zone" for Syrians to ride out the conflict. Mrs Clinton has also made the case for safe zones, as well as consistently proposing a no-fly zone.

Mr Trump told the crowd in Florida he did not believe polls that said he was trailing Mrs Clinton with women voters.

"I really think those polls are very inaccurate when it comes to women," he told the crowd.

"I think we're doing better with women than with men frankly. So we're setting records with men but I want to set records with women, to me, and I hate to tell the men this, but if I could swap I'd swap you out so fast."

But he continued to complain that the election is "rigged" in favour of Mrs Clinton.

Meanwhile, one of Mr Trump's top advisers acknowledged he was lagging behind Mrs Clinton, as the Democratic nominee pressed a strategy of encouraging early voting in key battleground states.

Trump campaign manager Kellyanne Conway said Mrs Clinton had "tremendous advantages", including a large campaign war chest that had allowed her to spend millions on television ads ahead of the Nov 8 election.

As the polling gap has widened, Mr Trump has said repeatedly the election is being "rigged" against him.

He has not offered evidence and numerous studies have shown that the US election system, which is decentralised and run by the states, is sound.