Christians United for Israel will welcome its millionth member Sunday night, cementing the evangelical group’s place as the largest US-based pro-Israel organization.

The group, known as CUFI, was founded in 2006, and had 500,000 members only two years ago. By contrast, the membership of AIPAC, the largest Jewish pro-Israel group in the United States, has about 100,000 members.

John Hagee, the controversial Texas-based evangelical preacher, founded the group hoping to harness the political power of the tens of millions of American evangelicals who support Israel. The organization has chapters in all the US states, and holds more than 40 pro-Israel events monthly.

US Christian evangelical support for Israel is a rapidly growing phenomenon, and CUFI’s impact on members of Congress, especially from the Republican Party, has increased significantly in the six years since its establishment, according to the Weekly Standard.

Recent surveys estimate the US evangelical population at up to 30 or 35 percent of the population, or about 90-100 million Americans. The American Jewish population, by comparison, is only 6.6 million people.

Prime Minister Benjamin Netanyahu will speak at a conference in Jerusalem marking the million-member milestone on Sunday, along with Hagee.