An alliance of U.S. Jewish groups sent a note on Wednesday to leaders of Israel's political parties, notifying them against full or partial annexation of the West Bank, Israeli Ynet News site has reported.

Authors of the letter said that it would be wrong for Israelis to believe that the UN administration will be always on the side of annexation plans, even though the administration of U.S. President Donald Trump appears to support land grab policies, said Ynet News.

"Simply put, the approach of this president does not represent the long-term interests and likely future policy of the United States," the letter warned.

The note also warned of the repercussions of Israel’s annexation policy on the relationship with U.S. Jewry, because "the vast majority of American Jews support a two-state solution to the Israeli-Palestinian conflict."

The letter was signed by 13 groups, including 10 members of the Progressive Israel Network, an umbrella coalition that includes J Street and the New Israel Fund.

Ahead of the September elections, Israeli Prime Minister Benjamin Netanyahu voiced his intent to hold sway over large swathes of the occupied West Bank if he wins the ballot.

Netanyahu's election pledge sparked a wave of international condemnation, with several states considering cutting down diplomatic ties with Israel should the annexation threat materialize on the ground.