More than 1,000 European parliamentarians wrote a letter yesterday advocating against Israel’s planned annexation of the West Bank.

The letter is addressed to European leaders, and calls on them to “act decisively” in preventing annexation by deliberating with international actors on the issue. It was signed by 1,080 parliamentarians from 25 European countries, including the United Kingdom.

Israeli Prime Minister Benjamin Netanyahu plans to annex Jewish settlements in Palestinian territory starting in July, and also wants to annex the Jordan Valley in the West Bank. Annexation enjoys support from the Israeli right, but many Palestinians say it will destroy their prospects for statehood. Much of the international community considers the West Bank, which Israel captured during the 1967 war from Jordan, as occupied by Israel.

The United States is open to annexation as part of the Donald Trump administration’s peace plan, but under certain conditions. The plan allows for Israel to annex parts of the West Bank, but also envisions an eventual Palestinian state. The Trump administration has been insisting that the partner of Netanyahu’s Likud party in the unity government, the Blue and White party, agree to annexation before it is to move forward.