Although saying that he does not foresee the Reform movement ending its Birthright trips to Israel, the group’s president said a new Israeli law has in effect erected a “giant unwelcome sign.”

The law bars foreign nationals from entry if they have advocated economic, cultural or academic boycotts of either Israel or the territory it controls beyond the Green Line.

Rabbi Rick Jacobs, president of the Union for Reform Judaism, told The Jewish Week Thursday that he sent an email yesterday to Prime Minister Benjamin Netanyahu asking him to clarify the law. He explained that some of those enrolled in upcoming Birthright trips “are worried that based on their opposition to settlement expansion they will be stopped at the border when they land in Israel.”

“There is ambiguity in the legislation,” the rabbi said in an interview, “but it is being read as covering a whole host of potential dissenters.”

Rabbi Jacobs pointed out that at a Holocaust observance earlier this week, Israeli President Reuven Rivlin said that “to disagree with Israel’s actions is not anti-Semitic, that [people who disagree with such actions] should not be denigrated, and that it is important to have a diversity of views.”

“The idea that they [Birthright participants] may have different views should not exclude admission,” Rabbi Jacobs said.

Last year, nearly 1,500 18-26-year-olds traveled to Israel as part of the Reform movement’s Birthright program. Rabbi Jacobs said Birthright surveys have found that 40 percent of those who have traveled to Israel through Birthright “identify with the Reform movement,” and that one-third of all Birthright participants between 2012 and 2016 came through the Reform movement.

Rabbi Jacobs said that if Netanyahu responds to his email by saying the law “may not be enforced across the board … it should not be a law. If it is on the books, we have a right to be concerned. We want assurances that differences with government policies is never a reason to exclude admission.”

“Our mindset is to bring more and more young people to Israel, but we have to be clear to the prime minister and his cabinet … that it is in Israel’s interest for this law not to exist.”