Donald Trump. Gretchen Ertl/REUTERS Real-estate mogul Donald Trump has hit a new high-water mark in the CNN/ORC survey, garnering 41% support among national Republican-primary voters in a poll released Tuesday.

That was more than double the support of Sen. Ted Cruz of Texas, Trump's closest rival in the GOP presidential primary. Cruz had the support of 19% of GOP voters in the survey. No other candidate hit double digits.

An ABC News/Washington Post poll published Tuesday found similar results, with Trump leading Cruz nationally 37% to 21%. Sen. Marco Rubio of Florida came in third at 11%, but no other Republican candidate ticked up to double digits.

That poll also found, significantly, that 64% of Republican voters viewed Trump as the most likely Republican nominee. And a majority — 56% — said Trump was the most electable potential nominee.

The poll results came out less than a week before Monday's caucus in Iowa, where the first votes of the 2016 primary will be cast. Trump and Cruz have been locked in an increasingly bitter back-and-forth ahead of the caucus, in which polls have shown the race tighter than in the national surveys.

A Quinnipiac University survey of the Hawkeye State released Tuesday found Trump leading Cruz there 31% to 29%. But Trump has led in seven of the past eight Iowa surveys after briefly falling behind Cruz in the state, according to RealClearPolitics. According to the website's average of six recent polls, Trump leads Cruz by about 6 points in the state.

Trump also finds himself in exceedingly good shape in polls of New Hampshire, which on February 9 will hold the first primary. A new Boston Herald/Franklin Pierce University poll released Monday night found Trump leading there with 33% support. Cruz was again his next-closest competitor, garnering 14% in the survey.