Prime Minister Benjamin Netanyahu said on Thursday that a US threat to withhold some arms would not prevent Israel from continuing its offensive in Gaza, indicating it might proceed with an invasion of the packed city of Rafah against the wishes of its closest ally. President Joe Biden has urged Israel not to go ahead with such an operation over fears it would exacerbate the humanitarian catastrophe in the Palestinian enclave. On Wednesday, he said the United States would not provide offensive weapons for a Rafah offensive, raising pressure on Netanyahu. But in a statement released Thursday, N…