In an open letter released on Wednesday, over 440 signatories called on the EU and its member states to respond to Israel’s intention to advance the E1 project, a proposed development spanning around 12 square kilometers that includes plans for approximately 3,400 housing units.

The project, located between east Jerusalem and the rest of the West Bank, would deepen territorial fragmentation by further separating Palestinian areas, according to the letter.

“The EU and its member states, together with partners, must take immediate action to deter Israel from further advancing its illegal annexation of Palestinian land in the West Bank,” the signatories said, advocating targeted sanctions including visa bans and business restrictions against individuals involved in settlement activity.

Among those endorsing the appeal were former EU foreign policy chief Josep Borrell and former Belgian prime minister Guy Verhofstadt.The letter cited Israeli plans to issue an initial construction tender on June 1, potentially enabling housing for up to 15,000 settlers, and urged swift diplomatic and economic measures to halt the initiative.

International concern over the E1 project has been longstanding, with the United Nations warning it could pose an “existential threat” to the viability of a contiguous Palestinian state.According to international law, Israeli settlements in the occupied West Bank are considered illegal, though Israel disputes this characterization.

More than 500,000 Israelis currently live in such settlements, alongside roughly three million Palestinians in the territory.

Data from the United Nations indicate that settlement expansion reached its highest level in recent years in 2025, while reports from Palestinian authorities and the UN point to a rise in violence involving settlers since the start of the Iran conflict in late February.

Israel has occupied the West Bank since 1967.