Biden is talking specifically about a ground invasion, not the bombing Israel is doing in Rafah right now. Via CNN.com:

President Joe Biden said for the first time Wednesday he would halt some shipments of American weapons to Israel – which he acknowledged have been used to kill civilians in Gaza – if Prime Minister Benjamin Netanyahu orders a major invasion of the city of Rafah.

“Civilians have been killed in Gaza as a consequence of those bombs and other ways in which they go after population centers,” Biden told CNN’s Erin Burnett in an exclusive interview on “Erin Burnett OutFront,” referring to 2,000-pound bombs that Biden paused shipments of last week.

“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,” Biden said.

So where exactly are the lines?

Biden said while the US would continue to provide defensive weapons to Israel, including for its Iron Dome air defense system, other shipments would end should a major ground invasion of Rafah begin.

“We’re going to 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,” he said. “But it’s, it’s just wrong. We’re not going to – we’re not going to supply the weapons and artillery shells.”