More than 30 former foreign ministers and prime ministers have signed a letter to the European Union, calling on the bloc to reaffirm its commitment to a two-state solution in the Middle East. 

The letter — addressed to EU chief diplomat Federica Mogherini and also given to Britain's The Guardian newspaper to publish — comes as US President Donald Trump prepares to unveil his administration's plan for the region.

The ex-officials wrote that Europe had worked with previous US administrations to promote a just resolution to the Israeli-Palestinian conflict, but lamented that the current US administration had "departed from longstanding US policy and distanced itself from established international legal norms."

Read more: Trump's Golan recognition: A dangerous precedent?

Key appeals and claims in the letter:

• The US administration "has so far recognized only one side's claims to Jerusalem and demonstrated a disturbing indifference to Israeli settlement expansion."
• Washington's funding cuts to the UN agency for Palestinian refugees was "gambling with the security and stability of various countries on Europe's doorstep."
• European leaders "should embrace and promote a plan" only if it respects the internationally agreed parameters for a two-state solution.
• Europe should "reject any plan" that does not involve the "creation of a Palestinian state alongside Israel" with "Jerusalem as the capital for both states."
• While working in partnership with the US would be ideal, "in situations in which our vital interests and fundamental values are at stake, Europe must pursue its own course of action."
• "Israel and the occupied Palestinian territories are sliding into a one-state reality of unequal rights. This cannot continue."

Read more: Opinion: As Israel's right wing triumphs, Palestine loses

What is the two-state solution? The two-state solution has long formed the basis of international efforts to resolve the Israeli-Palestinian conflict. It envisages an independent Palestinian state alongside Israel, with borders defined by pre-1967 lines. Israel objects to the idea of a Palestinian state, and has continued to build Jewish settlements in the occupied West Bank, drawing condemnation from the international community. There have been several pushes for peace, with the most recent formal international efforts breaking down in 2014.

A shift in US policy: There are concerns Trump's soon-to-be-unveiled Middle East plan will end Washington's decades of support for a two-state solution. Instead, Trump has angered Palestinians by recognizing Jerusalem as the capital of Israel and fostering a close relationship with Israeli Prime Minister Benjamin Netanyahu.

Read more: Germany emphasizes importance of two-state solution

Trump's peace plan: The US proposal was put together by a team that includes Trump's son-in-law, Jared Kushner. It is expected to be released once Netanyahu forms a governing coalition following his narrow election win. Palestinian leaders have already rejected the plan, citing Trump's past actions favoring Israel.

Read more: Trump's Golan proclamation gathers international condemnation

Who signed the letter to the EU? The signatories included Germany's former foreign minister, Sigmar Gabriel, as well as Jean-Marc Ayrault, Carl Bildt, Wlodzimierz Cimoszewicz and Guy Verhofstadt — former prime ministers of France, Sweden, Poland and Belgium respectively. Former NATO secretary generals Willy Claes and Javier Solana also added their names, along with former UK foreign secretaries David Miliband and Jack Straw.

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