The American Israel Public Affairs Committee is distancing itself from a political action committee that has run ads against Democratic presidential candidate Bernie Sanders.

The political action arm of Democratic Majority for Israel, formed last year to bolster the party’s support for Israel as its conservative government faces growing criticism from American progressives, ran a six-figure ad campaign in Iowa last month that questioned Sanders’ health and his ability to defeat President Donald Trump in November. Those ads prompted pushback from Sanders’ campaign, and a Friday report from the left-leaning website The Intercept asserted that AIPAC was helping Democratic Majority for Israel by allowing its donors to get AIPAC benefits from contributing to the group.

AIPAC spokesman Marshall Wittmann denied any such arrangement, saying by email that the organization “is not and has not been involved in the ad campaigns of any political action committee. The accusation that AIPAC is providing benefits to members for donating to fund these political ads or this political action committee is completely false and has no basis in fact.”

Rachel Rosen, spokeswoman for Democratic Majority for Israel, said the group is “completely independent” from “any other organization.”

AIPAC, founded more than six decades ago to support strong U.S.-Israel ties, has recently sparked criticism from the left for its opposition to former President Barack Obama’s nuclear agreement with Iran, among other issues. An alliance of liberal advocacy groups, including MoveOn and Indivisible, is leading an effort to push 2020 Democratic presidential hopefuls from attending AIPAC’s annual policy conference next month after mounting a similar effort last year.