"Just a few hours ago, the pier was successfully affixed to the beach in Gaza," said Vice Admiral Brad Cooper, deputy commander of US Central Command.

"I think we're going to get about 500 tons in in the next couple of days. It's a pretty substantial amount, and it's spread out over multiple ships right now," Cooper told reporters.

The humanitarian assistance is being screened in Cyprus and loaded by truck. Once on land, it will "move quickly," being offloaded from the coast into Gaza within hours.

"Thousands of tons of aid are in the pipeline. We're seeing significant volumes of aid flow into Cyprus for further distribution," he told reporters.

President Joe Biden announced the emergency pier in March to address the humanitarian crisis in the Gaza Strip, where the United Nations has warned of famine with virtually the entire population displaced by the Israeli military action in response to the October 7 Hamas attack.

Built at a cost of at least $320 million, the project is extraordinary in that such massive humanitarian efforts by the United States are usually in response to actions by hostile countries, not a US ally.

The United States said it had coordinated the effort with Israel.

Cooper said that around 1,000 US soldiers and sailors were involved in the operation but that they were only involved in the pier and not in delivery -- which will be handled through the United Nations -- or in combat between Israel and Hamas.

"There will be no US military boots on the ground in Gaza," he said.

Three additional US military ships will join the relief effort in coming days, with Britain also providing a vessel, Cooper said.