Donald Trump criticises Clinton's policies as Secretary of State

WASHINGTON: Republican US presidential frontrunner Donald Trump has accused his Democratic rival Hillary Clinton of "causing death and destruction" in her capacity as the Secretary of State, as the verbal duel between them escalated further.

Hours after Clinton, 68, deplored the "tone and inflammatory" rhetoric of her GOP rival's campaign, Trump, 69, on Twitter described her policies as the Secretary of State as stupid, which he claimed resulted in death and destruction.

"Hillary said 'I really deplore the tone and inflammatory rhetoric of his campaign.' I deplore the death and destruction she caused - stupidity," Trump said on Twitter last night.

Over the last few days, the mainstream media has seen a sudden eruption in verbal dual between the two leading presidential candidates.

A CNN/ORC poll released yesterday said Clinton, former Secretary of State, had a narrow edge over Trump - 49 per cent to 47 per cent - in a hypothetical general election matchup.

A day earlier, Clinton in an interview to Des Moines Register deplored the tone of Trump's campaign.

"I really deplore the tone of his campaign, the inflammatory rhetoric that he is using to divide people and his going after groups of people with hateful, incendiary rhetoric," she said.

"Nothing really surprises me anymore. I don't know that he has any boundaries at all. His bigotry, his bluster, his bullying have become his campaign. And he has to keep sort of upping the stakes and going even further," Clinton said.

It all started over the weekend, Clinton, during the Democratic Party's presidential debate, alleged that videos of Trump's anti-Muslim rhetoric was becoming a recruitment tool for ISIS.

Appearing over Sunday talk shows, Trump charged Clinton as a "liar" and making things up. At a campaign later in the evening, he used alleged sexiest remarks against the Democratic front runner.

Trump has 5.4 million followers on Twitter while Hillary has 4.9 million followers.