US Congressional staff are still furious about the letter by "Israel's" Ambassador to the US, Michael Herzog, accusing Democratic lawmakers of aiding the Palestinian Resistance group Hamas of misrepresenting Israeli policy and trying to influence US President Joe Biden.

One staffer said, "It really is a stunning document,” adding, "The tone of this letter is not reflective of the fact that the U.S. is the primary guarantor of Israel’s security. An unaware reader would assume that Israel is the superpower in this relationship and the U.S. the recipient of aid."

In the letter, first reported by Politico, Herzog said, "It seems that Hamas’ massive invasion on October 7th, its ruthless massacre of Israelis and the kidnapping of hostages to Gaza have been too easily forgotten."

The letter comes in response to a letter back on May 3 from Democrats to Biden warning him that "Israel" is breaching US law that prevents sending weapons to parties blocking American aid.

A second Democratic aide said, "Never before have we received such a harsh letter from the Israeli government. But then again, never before have we been so critical of their actions," while another staffer, a senior foreign policy aide, told HuffPost that the Israeli embassy also previously contacted some of the signatories of the May 3 letters.

With that being said, Herzog claimed that US lawmakers were not doing their jobs appropriately. 

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"It is disappointing that you have reached this determination on such a sensitive matter without having conducted sufficient due diligence to learn, check and corroborate the full facts of the matter, without requesting information from Israel, an ally of the United States, or listening to its side of the issue and without waiting for the U.S. Administration to reach its own conclusion, instead attempting to lead it towards a pre-determined one," Herzog continued.

"Denying Israel the weapons it needs to defeat Hamas and creating daylight between our countries on the basis of unsubstantiated claims may serve to embolden Hamas and fuel its perception that time is on its side."

'Disrespectful, but unsurprising'

The ambassador warned, "People who genuinely care about the security of Israel should be extremely careful in calling for curtailing U.S. security aid. ... Both friends and foes of the United States, in our region and elsewhere, are taking careful note and drawing conclusions."

However, Herzog and his staff didn't protest when seven Senators signed a March 12 letter arguing the same, a Senate aide told HuffPost, but that was released before Biden condemned "Israel" for blocking aid into Gaza and as arms shipments to "Israel" continued unabated. 

The first House aide called the Israeli letter and claims "embarrassing".

"It’s disrespectful but unsurprising from a government that has repeatedly made clear they do not care about the attitudes of the American public, or their representatives," the House aide added. 

Meanwhile, a spokesperson for the Israeli Embassy in Washington, DC, defended Herzog’s letter, and one aide told HuffPost that the Democratic Majority for "Israel", a pro-"Israel" group, urged Democrats not to sign the May 3 letter.

According to the aide, the organization is sending congressional offices copies of comments from National Security Advisor Jake Sullivan.

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This comes a day after it was reported that the Biden administration informed key lawmakers that it will provide "Israel" with more than $1 billion in additional arms and ammunition, according to what three congressional aides told the Associated Press on May 14. 

The $1 billion package will include about $700 million for tank ammunition, $500 million in tactical vehicles, and $60 million in mortar rounds, the congressional aides told AP on the condition of anonymity. 

Since Biden's administration put an arms transfer consisting of 3,500 bombs of up to 2,000 pounds each on hold this month, this is the first arms shipment to "Israel" to be revealed.