STORY: U.S. President Joe Biden publicly vowed for the first time on Wednesday to stop giving Israel weapons - if its forces make a full-scale invasion of Rafah, a city packed with refugees fleeing the war elsewhere in Gaza.

In an interview with CNN, Biden said:

"I made it clear that if they go into Rafah... I'm not supplying the weapons..."

He acknowledged in the interview that American bombs provided to Israel have killed civilians in the seven-month-old offensive in Gaza, which came in response to Hamas' attack on October 7.

The comments are the president's strongest public language to date, and underscore a growing rift between the U.S. and its closest Middle Eastern ally.

The interview was aired hours after Defense Secretary Lloyd Austin confirmed to the Senate that the U.S. had at least temporarily paused a planned delivery of thousands of heavy bombs.

And that Biden made the decision to hold on the weapons over concerns for Rafah.

That marks the first such delay since the U.S. administration pledged "ironclad" support to Israel.

"We learned that you have to protect civilians in the battlespace, otherwise you create more terrorists going forward."

The United States is by far Israel's biggest supplier of weapons, with Congress last month approving $26 billion in extra funding for the country.

Biden said the U.S. would continue to provide defensive weapons, including for Israel's Iron Dome anti-missile system.

But, referring to civilian casualties, he added: "It's just wrong...We're not going to supply the weapons and artillery shells."

The president is under growing pressure at home over American support for Israel, as he runs for re-election this year.

There was no immediate comment from Israel on Biden's remarks, but Israeli authorities have insisted Rafah must be hit, saying thousands of Hamas fighters are there.

Its forces have continued tank and aerial strikes on southern Gaza, after moving in via the Rafah border crossing with Egypt on Tuesday, which cut off a vital aid route.