Trump, Sanders take solid leads in first primary contests

Sanders opened up an eight-point lead over former Secretary of State Clinton, 51 per cent to 43 per cent

Just ten days before the first critical nominating contests, Republican presidential frontrunner Donald Trump has taken a commanding lead in Iowa while Bernie Sanders has overtaken Hillary Clinton in the Democratic race.

Real estate mogul Trump led Texas Senator Ted Cruz 37 per cent to 26 per cent in a new CNN/ORC poll Thursday in Iowa, where both parties hold their cacuses on February 1. Florida Senator Marco Rubio in third place at 14 per cent was the only other Republican in double digits.

Self styled Democratic Socialist Sanders, meanwhile, opened up an eight-point lead over former Secretary of State Clinton, leading her in Iowa 51 per cent to 43 per cent among likely Democratic presidential caucus-goers.

In December, Clinton led Sanders in Iowa by 18 points in CNN/ORC's polling, 54 per cent to 36 per cent.

As Sanders shot into the lead Clinton sought to turn his "establishment" attack right back on him-saying he served in Washington much longer than she did.

In a CNN interview, she also attacked his experience and fitness to lead the country, criticising his call during the last Democratic debate to "move as aggressively as we can to normalise relations with Iran."

Earlier at a rally in Indianola, Iowa, Clinton repeatedly referenced Sanders by name and questioned whether his ideas could ever become reality.

"I am not interested in ideas that sound good on paper but will never make it in the real world," Clinton said. "I care about making a real difference in your life and that gets to the choice you have to make in this caucus."

Sanders, on his part, told Time magazine that in national polls "we are defeating Donald Trump, the Republican's leading candidate, by far more than Hillary Clinton is."

"So if the question is, can a Bernie Sanders and what he stands for, and the fight for economic and social justice carry over to the general election and millions of working people? I think the evidence is that it can," he asserted.

Meanwhile, Trump ripped Cruz as a strident and unlikeable figure lacking the skills to negotiate and lead on behalf of the US.

"He had his moment and he blew it," Trump said at an event in a casino in Las Vegas Thursday after a reading a series of polls showing him surging in states around the country.

"He looks like a nervous wreck," he added. "He's going down." Trump also trashed former Florida Governor Jeb Bush as a "lost soul" and "a maniac."

"We've got a bunch of real dummies, I tell ya," he said adding, "Jeb is down the toilet and Ted is starting to go down."

He assured the crowd that if Bush halted his attacks on Trump, he would leave him alone.