A State Department official with over a decade of experience in the agency’s bureau that oversees U.S. arms sales resigned this week, citing what he called the U.S.’s “blind support” for Israel in its war with Hamas war and its continued “provision of lethal arms to Israel.”

Josh Paul, who served as director of congressional and public affairs for the State Department’s Bureau of Political-Military Affairs for more than 11 years, posted a letter about his resignation, dated Wednesday, to LinkedIn.

In the letter, which was first reported by HuffPost, Paul wrote that Hamas’ deadly attack on Israel was a “monstrosity” and criticized the Biden administration’s assistance to the country.

“I am leaving today because I believe that in our current course with regards to the continued — indeed, expanded and expedited — provision of lethal arms to Israel — I have reached the end of that bargain,” he wrote.

“I believe to the core of my soul that the response Israel is taking, and with it the American support both for that response, and for the status quo of the occupation, will only lead to more and deeper suffering for both the Israeli and the Palestinian people, and is not in the long term American interest,” Paul wrote. “This Administration’s response — and much of Congress’ as well — is an impulsive reaction built on confirmation bias, political convenience, intellectual bankruptcy and bureaucratic inertia.”

“That is to say, it is immensely disappointing, and entirely unsurprising,” he added. “Decades of the same approach have shown that security for peace leads to neither security, nor to peace. The fact is, blind support for one side is destructive in the long term to the interest of the people on both sides. I fear we are repeating the same mistakes we have made these past decades, and I decline to be a part of it for longer.”

Paul said that he has “deep personal ties to both sides of the conflict” and he wrote his master’s thesis on Israeli counterterrorism and civil rights. He also said he served for the U.S. Security Coordinator, “living in Ramallah while advancing security sector governance within the Palestinian Authority and liaising with the [Israel Defense Force].”

“I acknowledge and am heartened to see the efforts this Administration has made to temper Israel’s response, including advocating for the provision of relief supplies, electricity, and water to Gaza, and for safe passage,” he wrote. “In my role in the [Bureau of Political-Military Affairs], however, my responsibilities lie solidly in the arms transfer space. And that is why I have resigned from the U.S. Government, and from PM.”

Asked about the letter at a press briefing Thursday, a spokesperson for the State Department said they encourage people to speak up internally, but “we have made very clear that we strongly support Israel’s right to defend itself.”

“We are going to continue providing the security assistance that they need to defend themselves,” Matt Miller said at the briefing. “We think they have a right, not only a right but an obligation, to defend themselves against these terrorist attacks.”

He added that President Joe Biden and Secretary of State Antony Blinken have stated “very clearly that we expect Israel to abide by all international law it as they defend themselves, and we will continue to work with them to ensure that they meet the highest standards.”

Paul’s resignation letter was posted to Linkedin on the day of Biden’s latest trip to Israel, during which he reaffirmed his support for the country and said that he was planning to ask Congress for an “unprecedented support package for Israel’s defense.” Biden also announced $100 million in new U.S. funding for humanitarian aid to both the Gaza Strip and the West Bank.

During his remarks in Tel Aviv, Biden said that a “terrorist group in Gaza” was apparently responsible for the deadly blast at a Christian-run hospital in Gaza City that is estimated to have killed hundreds.

When asked what made him confident the Israelis were not behind the hospital explosion, Biden said: “The data I was shown by my Defense Department.” He did not provide any supporting evidence.

NBC News previously reported that the U.S. has an independent assessment that it was a Palestinian Islamic Jihad group rocket that misfired and hit the hospital in Gaza, according to two senior U.S. officials.

That would match what Israeli officials have said caused the blast. Palestinian health officials and Hamas have blamed an Israeli airstrike for the explosion, which they said killed almost 500 people.

The Biden administration is expected to submit to Congress this week a request for supplemental funding package that is likely to seek $60 billion for Ukraine, a lawmaker and two sources with knowledge of the request told NBC News on Wednesday. The rest of the request will include roughly $40 billion to provide aid to Israel, Taiwan and the U.S.-Mexico border.

Following his trip to Israel, Biden is scheduled deliver a prime-time foreign policy speech to the country on Thursday night, during which he’s expected to address the administration’s response to Hamas’ terrorist attacks against Israel and Russia’s war in Ukraine.

As of Thursday morning, more than 3,700 people have been killed and more than 13,000 have been injured in Gaza. In Israel, 1,400 people have been killed and 3,500 wounded.