Biden says US will not provide Israel with weapons to use in major Rafah invasion

President Joe Biden said Wednesday that American bombs have been used to kill civilians in Gaza and doubled down on his administration's plan to withhold weapons that Israel could use as part of a major invasion of Rafah.

More than a million Palestinians have sought refuge in the city in southern Gaza.

At least 30 people had been killed in Rafah since Tuesday, including women and children, the Al Kuwaiti hospital spokesperson in Rafah told ABC News. More than 33,000 have been killed overall in Gaza, according to the Hamas-run Gaza Ministry of Health.

"I know that you have paused, Mr. President, shipments of 2,000 pound U.S. bombs to Israel due to concern that they could be used in any offensive on Rafah. Have those bombs, those powerful 2,000 pound bombs been used to kill civilians in Gaza?" CNN's Erin Burnett asked Biden in a rare major network television interview.

"Civilians have been killed in Gaza as a consequence of those bombs and other ways in which they go after population centers," Biden answered.

"I made it clear that if they go into Rafah -- they haven't gone in Rafah yet -- if they go into Rafah, I'm not supplying the weapons that have been used historically to deal with Rafah, to deal with the cities, that deal with that problem."

"So it's not over your red line yet?" Burnett asked of Israel's current action in Rafah.

"Not yet. But it's -- we've held up the weapons. We've held up the one shipment. It's an old shipment. We've held that up," Biden said.

The White House on Tuesday called the Israeli incursion into Rafah "limited in scope" so far.

Israel on Wednesday appeared to downplay the U.S. withholding the bombs.

"We are responsible for the security interests of the State of Israel, and we are attentive to the interest of the United States in the region," Israel Defense Forces spokesman Daniel Hagari said.

Biden's comments to CNN were the most outspoken he's been to date publicly on how far he's willing to go to curtail U.S. aid to Israel.

Biden said the U.S. will "continue to make sure Israel is secure in terms of Iron Dome and their ability to respond to attacks that came out of the Middle East recently."

"But it's, it's just wrong. We're not going to -- we're not going to supply the weapons and artillery shells used, that have been used," Biden said.

Burnett also sought to nail down Biden's view of what Israel is doing in Rafah right now, and if he believes that qualifies as a major ground invasion in Rafah that he has told Israeli Prime Minister Benjamin Netanyahu would be a major mistake.

"No, they haven't gone into the population centers. What they did is right on the border. And It's causing problems with, right now in terms of -- with Egypt, which I've worked very hard to make sure we have a relationship and help," he said.

"But I've made it clear to Bibi and the war cabinet, they're not going to get our support, if in fact they go in these population centers," he added.

ABC News' Michelle Stoddart and Will Gretsky contributed to this report.