Updated 6:05 p.m. ET

Rick Santorum is surging in a new national survey, climbing to second place in the Gallup daily tracking poll.

Santorum, who swept contests in three states earlier this week, is now tied with a fading Newt Gingrich. Both have 20% support among registered Republican voters in the Gallup Poll.

INTERACTIVE: Poll tracker

Mitt Romney is still leading with 36%. Ron Paul is in fourth with 10% support.

The tracking poll is a five-day average and includes at least one day of polling since the former Pennsylvania senator won contests in Minnesota, Colorado and Missouri on Tuesday night.

Santorum's support in the Gallup daily tracking poll has grown 4 percentage points since interviews conducted Jan. 30-Feb. 3. Gingrich, meanwhile, has dropped 6 points since losing the Florida primary to Romney.