Former Secretary of State Hillary Clinton's lead over Sen. Bernie Sanders (I-VT) in South Carolina has narrowed to 21 points, according to a survey released Tuesday by the Democratic-leaning firm Public Policy Polling.

Billionaire real-estate magnate Donald Trump has expanded his lead over his Republican presidential rivals to 17 points in South Carolina, according to a survey released Tuesday by the Democratic-leaning firm Public Policy Polling. It's the first poll fielded in the state since Saturday’s GOP debate.

A Washington Free Beacon/TargetPoint Consulting poll released Friday shows between Democratic presidential candidates Hillary Clinton and Sen. Bernie Sander (I-VT) in Nevada. It's the first poll conducted in the state this year.

Former reality-television host Donald Trump has a substantial 16-point lead in the Republican primary contest in South Carolina on the heels of his New Hampshire primary victory, according to an Opinion Savvy poll released Friday.

The poll, which was the first taken in South Carolina since before the New Hampshire primary, also indicates that competition for second place remains tight in a spread that is consistent with much national polling and with most previous poll results.

Donald Trump maintained his solid lead in a national online tracking poll by NBC News/Survey Monkey released on Tuesday, despite a small dip in support, while Sen. Marco Rubio saw a small bump in support.

Trump earned 35 percent support from Republican and Republican-leaning voters, a 4-point drop from 39 percent in last week's tracking poll. Sen. Ted Cruz (R-TX) earned 20 percent support, which has not changed since last week's poll.

Hillary Clinton maintained a solid lead over Sen. Bernie Sanders (I-VT) in a national online tracking poll released by NBC News/Survey Monkey on Tuesday.

Clinton earned 51 percent support from Democrats and Democratic leaning voters, while Sanders earned 39 percent support, giving Clinton a 12-point lead. Clinton gained a percentage point from the tracking poll released last week, and Sanders' support remained the same.

Former reality-television star Donald Trump leads comfortably in New Hampshire's GOP primary, according to an Emerson College Polling Society poll released Monday, while in a somewhat surprising result former Florida Gov. Jeb Bush (R) comes in second place.

A CNN/WMUR tracking poll released Monday showed support for billionaire Donald Trump decreased by 2 points in New Hampshire since the previous poll released two days ago, while no other candidate registered a change in support of more than a single percentage point.

Donald Trump continues to lead the Republican presidential pack in New Hampshire by a wide margin, but Sen. Marco Rubio's surge to second place nearly disappeared in a tracking poll released by the University of Massachusetts Lowell on Monday.

Trump leads his competitors by 21 points, earning 34 percent support from likely Republican primary voters. The real estate mogul's support in the tracking poll has dropped 4 percentage points since the beginning of last week.

Sen. Bernie Sanders (I-VT) still maintains a strong lead in New Hampshire, even as Hillary Clinton has risen slightly over the past week, according to a tracking poll released by University of Massachusetts Lowell on Monday morning.

In the Monday poll, Sanders led Clinton by 16 points. Among likely Democratic primary voters, 56 percent supported Sanders and 40 percent supported Clinton.