Newt Gingrich has moved into the top tier of Republican presidential candidates, according to two national polls released Friday. 

The rise of the ex-House speaker comes as other candidates in the race encounter hurdles. Businessman Herman Cain spent the last two weeks fending off sexual harassment allegations. Texas Gov. Rick Perry capped off a string of shaky debate performances with an awkward moment Wednesday when he couldn't remember the three Cabinet departments he wants to eliminate. 

The new polls continue to show Cain and former Massachusetts Gov. Mitt Romney at the top. But Gingrich has carved out a space right alongside them. 

A McClatchy-Marist poll showed Romney leading with 23 percent, and Gingrich close behind with 19 percent. Cain was trailing slightly with 17 percent. 

A CBS News poll also released Friday showed Cain leading with 18 percent -- Romney and Gingrich were close behind with 15 percent each. 

Analysts for weeks have been suggesting that Gingrich could be primed for a surge. Romney has remained in the top tier in national surveys for months, while other candidates have quickly faded in the polls after enjoying an initial popularity burst. 

In debates, Gingrich has tried to stay above the fray, mostly resisting opportunities to attack his fellow Republicans and saving his criticism for President Obama

Both national polls were conducted after the allegations against Cain broke. 

The CBS poll of 382 GOP primary voters was taken Nov. 6-10. It had a margin of error of 5 percentage points. The McClatchy poll of 347 Republicans and GOP-leaning independents was taken Nov. 8-10. The margin of error was 5.5 percentage points.