"The campaign against Sanders originated with hybrid PAC Democratic Majority for Israel, a pro-Israel moderate group, that spent over $1.4 million against Sanders. The group spent over $800,000 running ads against the frontrunning Democratic presidential candidate in Iowa and it's spending $600,000 in Nevada", the Center for Responsive Politics said on Friday citing Federal Election Commission filings.
Earlier this month, the Intercept reported that the super PAC is closely tied to the American-Israel Public Affairs Committee (AIPAC).
Sanders, although actually Jewish himself, has been one of the few candidates in either party to criticise the Israeli state's policies towards Palestine.
The Democratic candidates will compete in the Nevada caucuses on Saturday, the third primary contest. Sanders and former Indiana Mayor Peter Buttigieg are leading the field with Senator Elizabeth Warren, former Vice President Joe Biden, and Senator Amy Klobuchar rounding out the top five.