Detroit, Michigan - Democratic candidate for US Senate Hill Harper was reportedly offered $20 million by a big-money donor to drop out of the race and instead launch a challenge to Congresswoman Rashida Tlaib.

"I didn't intend for a private phone call to turn public. But now that it has, here's the truth," Harper wrote on X on Wednesday.

"One of AIPAC's biggest donors offered $20m if I dropped out of the U.S. Senate race to run against Rashida Tlaib," he continued. "I said no. I won't be bossed, bullied, or bought."

Politico reported the October 16 offer and named Michigan businessman Linden Nelson, who has past ties to the American Israel Public Affairs Committee (AIPAC), as the donor.

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Harper is taking on US Representative Elissa Slotkin in the 2024 Democratic primary to replace retiring Senator Debbie Stabenow. The former CSI: NY actor and SAG-AFTRA union member supports universal health care, minimum wage increases, reproductive freedom for all, and comprehensive criminal justice reform, as well as a humanitarian ceasefire in Gaza.

AIPAC has denied that Nelson was acting on the group's behalf in reaching out to Harper.

AIPAC has a history of spending big to defeat progressive women of color in races around the country.

The pro-Israel lobby group is reportedly prepared to invest $100 million in the 2024 election cycle and is aiming to eject the Squad, including Rashida Tlaib.

AIPAC-backed challengers have already come forward to take on Representatives Cori Bush, Jamaal Bowman, Summer Lee, and Ilhan Omar.

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Tlaib, the only Palestinian-American in Congress, was censured in the House earlier this month for her use of the slogan "From the River to the Sea," which has a contested meaning.

The Michigan Democrat is one of 18 co-sponsors of H.Res. 786 calling for an immediate ceasefire in Israel's assault on Gaza.