The Washington Post reports that Congress was officially notified of the proposed sale on 5 May, citing three people familiar with the notification — a week before the current conflict with Hamas began.
Rockets fired from Gaza into Israel have led to the deaths of 10 Israelis. Airstrikes on Gaza have left almost 200 Palestinians dead.
The Biden administration has called for a ceasefire but also maintains that Israel has the right to defend itself.
While a large majority of Congress backs this position, a growing minority of Democrats, particularly in the House of Representatives, have raised concerns about supporting Mr Netanyahu and question the timing of the sale.
Some suggest using the sale as leverage to push for a ceasefire.
“In the past week, the Israeli military's strikes have killed many civilians and destroyed the building that housed the Associated Press, an American company reporting on the facts in Gaza,” a Democratic lawmaker on the House Foreign Affairs Committee told the Post.
“Allowing this proposed sale of smart bombs to go through without putting pressure on Israel to agree to a ceasefire will only enable further carnage.”
After official notification of a weapons sale, Congress has 15 days to object by way of a non-binding resolution of disapproval.
Most of the deal with Boeing is for Joint Direct Attack Munitions which transform bombs into precision-guided missiles.
Israel maintains it uses precision-guided munitions to minimise civilian casualties, accusing Hamas of using its own people as human shields in the densely populated Gaza Strip.
Given the majority support for Israel in Congress, it is unlikely that action will be taken to block the sale, but coming during the middle of the current conflict, it has highlighted a growing split in the Democrat ranks over the special treatment the ally receives.
Younger lawmakers, in particular, are more open to criticising Israel’s actions, and this has opened the way for criticism from those that defend the country as the death toll in Gaza mounts.
“I am deeply troubled by reports of Israeli military actions that resulted in the death of innocent civilians in Gaza as well as Israeli targeting of buildings housing international media outlets,” said Senator Robert Menendez, chairman of the Senate Foreign Relations Committee in a statement over the weekend.
Congressman Mark Pocan of Wisconsin tweeted: “We cannot just condemn rockets fired by Hamas and ignore Israel’s state-sanctioned police violence against Palestinians — including unlawful evictions, violent attacks on protestors & the murder of Palestinian children. US aid should not be funding this violence.”
New York representative Alexandria Ocasio-Cortez labelled Israel an “apartheid state” on Twitter saying that it could not be considered a democracy.
She also tweeted: “This is happening with the support of the United States. I don’t care how any spokesperson tries to spin this. The US vetoed the UN call for ceasefire. If the Biden admin can’t stand up to an ally, who can it stand up to? How can they credibly claim to stand for human rights?”