The specter of an Israeli invasion of Rafah has sparked a resurgent debate among Democrats in Washington over whether aid to the country should be tied to human rights conditions, according to Axios news website.

A group of progressive senators led by Sen.

Bernie Sanders sent a letter to Biden calling for him to condition aid on the facilitation of humanitarian aid into Gaza.

'We urge you to make it clear - that failure to immediately and dramatically expand humanitarian access and facilitate safe aid deliveries throughout Gaza will lead to serious consequences,' they wrote.

The letter follows a call from a group of House Democrats last week for Biden to considering suspending aid if Israel invades Rafah.

Both letters focus on a national security memo Biden signed last month requiring 'Israel' to abide by international law in its use of US weapons and allow humanitarian aid into Gaza.

Some pro-Israel House Democrats made clear to Axios they would oppose conditioning aid under any circumstances.

'I'm not for conditioning aid.

We don't condition aid now, we shouldn't condition aid,' Rep.

Debbie Wasserman Schultz told Axios.

Rep.

Kathy Manning said it is 'critically important for Israel to make sure that Hamas can't come back' and that the US should 'continue to stand shoulder to shoulder with our democratic ally.'