A confidant of Prime Minister Benjamin Netanyahu confirmed that the Israeli leader’s plan to annex parts of the occupied West Bank would not start on Wednesday, the original target date, as the British Prime Minister made an extraordinary appeal to Israel to call off the plan.

The developments cast further uncertainty over whether Israel will ultimately follow through on the explosive annexation initiative, which has drawn fierce international condemnations from some of Israel’s closest allies.

Speaking on Israel’s Army Radio station, Cabinet Minister Ofir Akunis confirmed that the annexation process would not begin on Wednesday, saying that officials were still working out the final details with their American counterparts. He said he expected the annexation to take place later in July.

“Coordination with the American administration is not something that can be dismissed,” he said.

Mr. Netanyahu had said that he wants to begin annexing West Bank territory in line with President Donald Trump’s Mideast plan.

The Prime Minister’s Office issued a statement saying Mr. Netanyahu held discussions on Wednesday with American diplomats and Israeli defence officials on the issue of annexation, and that “additional discussions will be be held in the coming days.”

The plan, unveiled in January, envisions bringing some 30% of the territory under permanent Israeli control, while giving the Palestinians limited autonomy in carved-up pockets of the remaining land. But the plan has come under stiff criticism. The United Nations, the European Union and key Arab countries have all said Israel’s annexation would violate international law.