Bernie Sanders is leading in Wisconsin, just days before the next primary.

FOX's Jared Halpern has more:

Bernie Sanders is looking to keep a string of wins going next week in Wisconsin.

A FOX Business Network poll shows he is leading overall frontrunner Hillary Clinton, but both campaigns are looking ahead to what could be make or break New York primary. Polls show Clinton in front, but her lead narrowing, as attacks sharpen:

(Clinton) "I am so sick of the Sanders campaign lying about me."

Clinton telling a Greenpeace activist the Sanders campaign is "lying" about her taking donations from oil companies. A campaign spokesman says the candidate has never accepted funds from the oil and gas industry.

In Washington, Jared Halpern, FOX News.