The United States on Saturday welcomed the arrival of aid trucks from Egypt in the war-torn Gaza Strip, and urged all parties to keep the Rafah crossing open.

"The opening of this essential supply route was the result of days of diplomatic engagement at the highest levels," President Joe Biden said in a statement.

"I made it clear from the outset of this crisis — in both my public statements and private conversations — that humanitarian assistance was a critical and urgent need that had to get moving," he said.

US Secretary of State Antony Blinken earlier urged "all parties to keep the Rafah crossing open to enable the continued movement of aid that is imperative to the welfare of the people of Gaza."

AFP journalists on Saturday saw 20 trucks from the Egyptian Red Crescent, which is responsible for delivering aid from various UN agencies, pass through the Rafah border crossing from Egypt into Gaza.

"We have been clear: Hamas must not interfere with the provision of this life-saving assistance," Blinken said. "Palestinian civilians are not responsible for Hamas's horrific terrorism, and they should not be made to suffer for its depraved acts."

The opening of the supply route came after days of intense negotiations and an agreement reached by Biden with Israeli Prime Minister Benjamin Netanyahu and Egyptian President Abdel Fattah al-Sisi during Biden's visit to Israel earlier this week.

Saturday's was the first such delivery since the war broke out two weeks ago between Israel and Hamas, the Islamist militant movement which rules the Palestinian enclave of 2.4 million people.

On October 7, Hamas militants stormed into Israel from Gaza and killed at least 1,400 people, mostly civilians who were shot, mutilated or burned to death on the first day of the raid, according to Israeli officials.

Since then, more than 4,300 Palestinians, mainly civilians, have been killed in relentless Israeli bombardments, according to Gaza's Hamas-run health ministry.

Biden said Washington would "continue working to protect civilians, consistent with obligations under international humanitarian law."

He added that US diplomatic efforts were continuing to allow for Americans and their immediate families in Gaza to safely leave the territory.