US troops have begun construction of a maritime pier off the coast of Gaza that aims to speed the flow of humanitarian aid into the territory, the Pentagon has said, but the complex plan to bring more desperately needed food to Palestinian civilians is still mired in fears over security and how the aid will be delivered. “I can confirm that US military vessels, to include the USNS Benavidez, have begun to construct the initial stages of the temporary pier and causeway at sea,” Pentagon spokesperson Maj Gen Patrick Ryder told reporters. About 1,000 US troops will support the military effort, including in coordination cells in Cyprus and Israel. The US president, Joe Biden, has ordered forces to not step foot on the Gaza shore. A third party will be driving trucks down the pier on to the beach. Concerns about the risk to American troops getting caught up in the conflict were underscored on Thursday as news emerged of a mortar attack near the area where the pier will eventually touch ground. No US forces were present, however a UN team inspecting the site were forced to take shelter. In a statement, the Israeli military said it would provide security and logistics support for the pier and an Israeli military brigade, which includes thousands of soldiers, along with Israeli Navy ships and air force, would work to protect US troops who are setting up the pier. A senior US military official told reporters that the US is on track to begin delivering aid using the new port and pier by early May. The official said deliveries through the sea route initially will total about 90 trucks a day and could quickly increase to about 150 trucks daily. Aid groups have said they have broad concerns about their safety and reservations about how Israeli forces will handle security. Sonali Korde, an official with the US Agency for International Development, told Associated Press (AP) that key agreements for security and handling the aid deliveries were still being negotiated. Those include how Israeli forces will operate in Gaza to ensure that aid workers are not harmed. Aid groups have been shaken by the deaths of seven World Central Kitchen workers in an Israeli airstrike on 1 April as they travelled in clearly marked vehicles on a delivery mission authorised by Israel. The UN’s World Food Program has agreed to lead the aid delivery effort, but its deputy executive director said on Thursday that the group must be able to operate in a safe and secure way. A UN official said the port will probably have three zones – one controlled by the Israelis where aid from the pier is dropped off, another where the aid will be transferred, and a third where Palestinian drivers contracted by the UN will wait to pick up the aid before bringing it to distribution points. A senior Biden administration official said aid coming off the pier will need to pass through Israeli checkpoints on land. That is despite the aid having already been inspected by Israel in Cyprus prior to being shipped to Gaza. Israel wants to prevent any aid getting to Hamas fighters that boosts their war effort. The construction of the new port in the Gaza Strip appears to have been moving quickly over the last two weeks, according to satellite images analysed by AP. The port sits just southwest of Gaza City, a bit north of a road bisecting Gaza that the Israeli military built during the fighting. The area once was the territory’s most-populous region, before the Israeli ground offensive rolled through, pushing over 1 million people south toward the town of Rafah on the Egyptian border. Biden announced the pier in March as aid officials implored Israel to ease access for relief supplies into Gaza over land routes.