A coalition of 21 countries, including the United Kingdom, Australia and Japan, has strongly condemned Israel’s plan to push ahead with building a major settlement in the occupied West Bank, warning it could kill off any chance of a two-state solution.

In a joint statement released on Thursday, the countries said Israel’s move was a “violation of international law” and called for its “immediate reversal.”

The plan, often referred to as E1, involves constructing 3,400 homes for Israeli settlers on land east of Jerusalem. Critics say it would carve up the West Bank, sever access to East Jerusalem — which Palestinians want as their future capital — and link together existing Israeli settlements.

The signatories include Belgium, Canada, Denmark, Estonia, Finland, France, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, the Netherlands, Norway, Portugal, Slovenia, Spain and Sweden, alongside the UK, Australia and Japan.

Their message was blunt: the project “risks undermining security, fuels further violence and instability, and brings no benefit to the Israeli people.”

The Palestinian Authority, the European Commission and United Nations Secretary-General Antonio Guterres have also spoken out against the project.

The EU added earlier this month that “ongoing settler violence and military operations” combined with unilateral moves like E1 were making an already volatile situation worse and “further eroding any possibility for peace.”