The US said no American forces would go ashore and an unnamed "third party" would drive trucks along the floating causeway on the beach.
The UK is understood to be considering handing over the task to British troops when the aid corridor opens next month. Whitehall sources said no decision had been taken and the matter had yet to cross the Prime Minister's desk.
The Ministry of Defense (MoD) and the Israeli army declined to comment. Britain was closely involved in the planning of the seaborne aid operation, and Defense Secretary Grant Shapps said the UK "continues to play a leading role in providing support in collaboration with the US and other international allies."
The likely role for British forces - known as "wet boots" by military planners - would see them drive trucks from landing craft onto temporary causeways and support a safe distribution area ashore.
Although a huge effort will be made to protect allied forces far and wide, British troops will potentially face a high risk of attack by Hamas and other armed groups. On Wednesday, mortars fell close to the designated distribution zone, forcing a UN team to seek shelter.
US defense officials have confirmed that an American military ship has begun construction of a large floating pier in the Eastern Mediterranean. Large ships from Cyprus will transport aid, which will then be moved to trucks and tiny landing craft. "Several hundred meters long" and securely fastened to the sand, that was the stated length of the floating causeway.
They said they hoped the new maritime corridor - which they called Joint Logistics Over-the-Shore (JLOTS) operations - would eventually deliver 150 trucks a day. The IDF has pledged to provide security for the sea aid
The aim is to supplement - but not replace - aid delivery through land which is still insufficient to meet needs An average of about 220 aid trucks are currently arriving by road into Gaza each day. The Israel Defense Forces (IDF) said it would "provide security and logistics support for the JLOTS initiative... to increase humanitarian access to the Gaza Strip".
The Israeli military will be responsible for anchoring the floating causeway to the beach and is practicing how to do this with American forces further north on the Israeli coast. A senior US military source told reporters at a briefing that hundreds of US soldiers and sailors would be living and sleeping at sea on a UK ship, RFA Cardigan Bay, as there would not be American boots on the ground.
He also clarified that US forces would not take aid ashore and instead that role would be handled by a "significant partner". He confirmed that it would be another country, not a private military company. "We have a third party that will take the trucks down the pier," the US military official said. "Emphasis added, there will be no US military boots on the ground. So, third parties are driving those trucks."
A UK source said nothing had been decided but "do we put wet boots on the beach, do we drive trucks on the wharf?" There is a debate going on. Mr. Shapps stated that the crews aboard RFA Cardigan Bay were essential to the UK's participation and added, "It is vital that we establish more routes for vital humanitarian aid to reach people in Gaza." The Ministry of Defense declined to comment on the idea that UK forces may drive trucks ashore.
He said specialist British military planning teams had been embedded for weeks in Tampa, Florida - as well as US operational headquarters in Cyprus - to help develop the safest and most effective sea routes. The UK Hydrographic Office also shared analysis of the Gazan coast with US planners for pier development.
More than six months into Israel's military campaign in the Gaza Strip, more than half of its 2.2 million people have entered the southern city of Rafah. The United Nations has warned of a humanitarian disaster and Israel has faced international criticism for limiting the amount of aid reaching civilians by land.
The Hamas-run health ministry in Gaza says more than 34,000 people have been killed in Gaza since the war began on October 7. The IDF launched the offensive after about 1,200 Israelis and foreigners - mostly civilians - were killed and 253 were taken back to Gaza as hostages, according to Israeli figures.
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