"Before Hanukkah turns into Christmas, it's time to come back to Israel." This is the tag-line of a recent campaign launched by Israel's Ministry of Absorption persuading Israeli expats in America to return to their homeland.

The campaign is centred on the notion that Israelis living in the United States for long periods of time will become assimilated into American culture, thereby losing their Jewish heritage.

Billboards have been erected in U.S. cities with large Israeli populations, including New York, Los Angeles and Palo Alto bearing slogans such as "Before 'Abba' turns into 'Daddy', it's time to come back to Israel," and "Before 'Motek' turns into 'Honey', it's time to come back to Israel."

The ministry also posted videos on its website showing "assimilated" Israeli families. In one of the videos, an Israeli grandmother talking via Skype to her granddaughter in America asks her if she knows what holiday it is. The girl answers "Christmas!" prompting her parents to exchange worried looks.

The campaign has prompted heavy criticism from both Jewish and non-Jewish members of congress. As well as being "demeaning" to American Jewry, they said, the campaign could also be viewed as degrading Christmas.

"We find these videos heavy-handed, and even demeaning," said Abraham Foxman, national director of the ADL. "While we appreciate the rationale behind the Israeli government's appeal to its citizens living in the U.S. to return to Israel, we are concerned that some may be offended by what the video implies about American Jewry."

Haaretz newspaper reports that a senior Israeli Foreign Ministry official "expressed dismay that a campaign that risked insulting American Jews had been mounted without consulting with his ministry."

"We only found out about it from the complaints that reached the consulates," the official said.

The Ministry for Absorption says the campaign was launched in response to surveys taken among Israelis living in the United States, and that the feedback has been positive.

"The State of Israel invests a great effort in encouraging all of its citizens who reside abroad to return to Israel," says a statement on the ministry's website.