Republican presidential nominee Donald Trump has narrowed the gap in critical swing state Pennsylvania, due largely to increasingly hostile views against his opponent.

Multiple polls indicate Hillary Clinton still holds a solid lead in the Keystone State. However, her negatives are surging.

Franklin & Marshall College's latest measure of the election shows a stunning plunge in Clinton's "net favorability," or the difference between voters who view her positively against those who view her negatively. The gap in the F&M poll went from -2 after the Democratic convention to -16 in the poll taken from Aug. 25-29.

The poll shows an even bigger gap than at the national level, where Clinton's favorability is at -13.3, according to the Real Clear Politics average.

Overall in Pennsylvania, Democrat Clinton holds a 7-point advantage over Trump among likely voters, down from the 11-point lead after her party's convention in late July. The margin is even closer among registered voters, where the edge is just 4 points, at 47 percent to 43 percent.

Both candidates have made multiple stops in the state recently to shore up support.