Sen. Bernie Sanders (I-VT) holds a commanding lead in New Hampshire over former Secretary of State Hillary Clinton, according to a University of Massachusetts-Lowell tracking poll released Thursday, but the gap between the two has begun to narrow since Clinton’s wafer-thin victory in the Iowa caucuses.

The UMass daily tracking poll, which releases daily results collating in-person interviews from the preceding three days, showed support for Sanders at 58 percent to Clinton’s 36 percent. Although this result is consistent with polling showing Sanders leading in New Hampshire for most of the fall and winter, the tracking results suggest that Clinton has gained some momentum. Her numbers are up four points from yesterday’s 32 percent and from 30 percent when tracking began. By contrast, Sanders, whose strongest showing was 63 percent of support in Tuesday’s tracking poll, had dropped to 61 percent Wednesday.

The UMass daily tracking poll, sponsored by local news station WHDH, was carried out from Feb. 1-3. Pollsters surveyed 420 likely Democratic voters with a margin of error of 5.3 percentage points.

This post has been updated.