Fiery real estate mogul and reality TV star Donald Trump continues to solidify his grip of the lead in the 2016 Republican presidential race even as his closest rival, former Florida Gov. Jeb Bush, dropped to third place in the latest survey among Republican voters nationwide.

A week before the inaugural Republican presidential debate, the 69-year-old Trump is well ahead of the pack with the support of 20 percent of Republicans in the Quinnipiac Poll released on Thursday.

Wisconsin Gov. Scott Walker overtook Bush at second place with 13 percent support. Bush fell to the number 3 spot at 10 percent. No other Republican candidate polled higher than 6 percent, with nine of the 12 remaining candidates polling within a statistical tie.

Also on Thursday, the GOP race became even more crowded with the entry of former Virginia Gov. Jim Gilmore as the 17th Republican presidential primary candidate.

"I am a candidate for president because our current Washington leadership is guiding America on a path to decline, and I can reverse that decline," Gilmore said in a video message to supporters.

Gilmore, a former Army intelligence officer, served as Virginia's governor from 1998 to 2002.

Thursday's poll is expected to be one of the five surveys that will be considered in determining the GOP candidates who will be invited in the debate, which will be sponsored by Fox News and Facebook. Fox News said it may invite more than 10 candidates on stage in the event of a tie.

In Thursday's Quinnipiac Poll results, retired neurosurgeon Ben Carson, former Arkansas Gov. Mike Huckabee, Sen. Rand Paul, and Sen. Marco Rubio each polled at 6 percent, followed by Sen. Ted Cruz and Ohio Gov. John Kasich at 5 percent.

New Jersey Gov. Chris Christie got 3 percent to round out the top 10.

The rest of the field saw Louisiana Gov. Bobby Jindal and former Texas Gov. Rick Perry getting 2 percent each. Former Sen. Rick Santorum, former HP CEO Carly Fiorina, and former New York Gov. George Pataki each received 1 percent..

The Reuters/Ipsos poll earlier showed that 25 percent of Republican voters would want to elect Trump as the GOP nominee to oppose Democratic frontrunner, former US Secretary of State Hillary Clinton, in the 2016 US presidential polls.

The survey result gave Trump a double-digit advantage over Bush, who was trailing behind with 12 percent.

"It is a huge jump for Trump, who announced his candidacy for November 2016 election six weeks ago—and this despite the criticism political rivals leveled at him for his remaks this month belittling the military service of Senator John McCain," Reuters said in its report.

"The five-day rolling online poll had Trump at 15 percent among Republicans on Friday before he rocketed to 24.9 percent on Tuesday," the wire agency noted.

Reuters also noted that if Trump decides to mount an independent presidential bid in a three-way race for next year's US presidential polls, he might drain support from the Republican nominee, and help the Democratic candidate cruise to victory.

The Reuters survey results also showed that Trump has about the same 23 percent chance as Bush to beat Clinton in a head to head match-up.

Meanwhile, a separate state poll found Trump beating Bush in the latter's home