US President Joe Biden and Israeli Prime Minister Benjamin Netanyahu laid out contradictory "red lines" about the war in Gaza in recent days that could put them on a collision course if Israel invades Rafah in southern Gaza in the next few weeks, three US officials told Axios.

No decisions have been made about how the U.S. would respond to an Israeli operation in Rafah, but two US officials said one of the options discussed internally between the White House, the State Department and the Pentagon is to impose restrictions on the use of U.S.-made offensive weapons by the Israeli army in Gaza.

A third US official said it is likely that an Israeli operation in Rafah will lead to the U.S. allowing a UN Security Council resolution calling for an immediate ceasefire to pass. The US has vetoed resolutions brought to the Security Council three times since the beginning of the war.

In an interview with MSNBC on Saturday, Biden was asked whether an Israeli military operation in Rafah was a red line for the administration. "Yes, it is," Biden replied.

A day later, Netanyahu pushed back in an interview insisting that Israel will go for the operation and saying that his red line is that October 7 doesn't happen again.

Biden and Netanyahu haven't spoken since 15 February, according to Axios.

In their last call, Biden expressed concern about a possible Israeli operation in Rafah, the White House said.

Meanwhile, US Politico reported that Biden may also consider conditioning military aid to Israel if it moves forward with a large-scale invasion of Rafah, according to four US officials with knowledge of internal administration thinking.

While Biden has not made any decision on limiting future weapons transfers, officials said that he very well might do so if Israel launches a new operation that further imperils Palestinian civilians.

“It’s something he’s definitely thought about,” said one of the officials.

White House deputy press secretary Olivia Dalton told reporters on Air Force 1 on Monday that Biden was clear in his MSNBC interview, and that no military operation should take place in Rafah "if there is not a credible and implementable plan to take care of the safety and security needs of the more than a million civilians who are sheltering there. And we've seen no such plan."

Breach of US aid

A group of US Democratic senators urged Biden to stop providing offensive weapons to Israel until it lifts restrictions on US-backed humanitarian aid going into Gaza, The New York times reported.

In a letter to Biden, Senator Bernie Sanders, independent of Vermont, and seven Democrats argued that by continuing to arm Israel, Biden was violating the Foreign Assistance Act, which bars military support from going to any nation that restricts the delivery of humanitarian aid.

It was the latest bid by members of his own party to intensify pressure on Biden to use his leverage to demand that Prime Minister Benjamin Netanyahu change his tactics and mitigate the suffering of the Palestinians.

“We urge you to make it clear to the Netanyahu government that failure to immediately and dramatically expand humanitarian access and facilitate safe aid deliveries throughout Gaza will lead to serious consequences, as specified under existing US  law,” the group wrote.

Sanders said it was clear that Netanyahu’s actions were in breach of the terms of American military aid as set out in the Humanitarian Aid Corridor Act, which is part of the foreign assistance law.

The act says that as soon as the president is made aware that a country is blocking or restricting the delivery of American humanitarian assistance, no US military aid can be provided.

“That’s exactly what Israel is doing; they are preventing US humanitarian assistance from getting to the people of Gaza,” Sanders said in an interview. “They are in violation of the law, and therefore financial aid should be suspended,” the American daily added.

But so far, Congress has shown no ability to use its own leverage to try to change Israel’s behavior. Proponents of restricting military aid or conditioning it to a change in conduct by Netanyahu lack the votes to win adoption of such measures in either the House or the Senate. 

Last month, the Senate approved an emergency national security aid bill that would send an additional $14.1 billion in military aid to Israel, including $10 billion for offensive weapons for the war against Gaza.

The letter draws a distinction between defensive aid for Israel, such as the Iron Dome, and the military assistance that would go toward furthering Israel’s assault on the Gaza Strip.