WASHINGTON — Representative Alexandria Ocasio-Cortez, Democrat of New York and the highest-profile progressive in the House, apologized on Friday to her constituents for an abrupt decision to pull back her vote against providing $1 billion in new funding for Israel’s Iron Dome missile defense system, suggesting she said had done so after being subjected to “hateful targeting” for opposing it.

Ms. Ocasio-Cortez, a member of the liberal group known as the Squad, was one of two members who voted “present” as the measure to help Israel replace missile interceptors overwhelmingly passed the House on Thursday on a vote of 420 to 9. She was seen weeping on the House floor after she switched her vote from “no” to “present.”

The episode captured the bitter divide among Democrats over Israel, which has pit a small but vocal group of progressives who have called for an end to conditions-free aid to the country against the vast majority of the party, which maintains that the United States must not waver in its backing for Israel’s right to defend itself.

In a lengthy letter on Friday, Ms. Ocasio-Cortez told her constituents that she opposed the funding, citing “persistent human rights abuses against the Palestinian people,” and had pleaded with top Democrats to delay the vote.

“The reckless decision by House leadership to rush this controversial vote within a matter of hours and without true consideration created a tinderbox of vitriol, disingenuous framing, deeply racist accusations and depictions,” Ms. Ocasio-Cortez wrote.

After the vote, Ms. Ocasio-Cortez drew condemnations on social media both from supporters of Israel, who savaged her for failing to support the funding, and from progressives and pro-Palestinian activists, who expressed outrage that she ultimately did not register her opposition to it.

“To those I have disappointed — I am deeply sorry,” she wrote to residents of New York’s 14th Congressional District, which includes parts of the Bronx and Queens. “To those who believe this reasoning is insufficient or cowardice — I understand.”

At issue was the House’s effort to provide additional funding for Israel’s Iron Dome system, which was used during heavy fighting between Israel and Hamas in May. The debate on the House floor grew bitter Thursday as some progressive Democrats who were opposed called Israel an “apartheid state,” an accusation that at least one proponent of the bill called antisemitic.

Ultimately, only eight Democrats — as well as one Republican, Representative Thomas Massie of Kentucky — opposed the measure.

“Yes, I wept,” Ms. Ocasio-Cortez told her constituents on Friday. “I wept at the complete lack of care for the human beings that are impacted by these decisions, I wept at an institution choosing a path of maximum volatility and minimum consideration for its own political convenience.”

The dispute began this week, after progressives revolted at the inclusion of the Iron Dome funding in an emergency spending bill, effectively threatening to shut down the government rather than support the money. Democratic leaders were forced to strip it out of that bill, which passed the House on Tuesday, and arranged a separate vote to approve the Iron Dome money.

Some progressive lawmakers grew furious with Representative Steny H. Hoyer of Maryland, the No. 2 Democrat, who pushed for the swift vote on Iron Dome funding. His maneuver appeared to be intended to calm Israeli officials, who had watched the dispute with alarm.

Yair Lapid, Israel’s foreign minister, called Mr. Hoyer and emphasized the need for the House to approve the request as soon as possible, according to an account of the call released by Mr. Lapid’s office. Mr. Hoyer assured him that the decision to drop it from the government spending measure had been no more than a “technical delay,” the account said. Hours later, Mr. Hoyer announced that the House would hold a separate vote to approve the funding later in the week.

Ms. Ocasio-Cortez said she had personally appealed to Mr. Hoyer to delay the vote. Mr. Hoyer did not immediately respond to a request for comment.

“Even the night before, as it became clear that the discourse around this issue was quickly devolving from substance to hateful targeting, I personally had a call with the House majority leader to request a 24-hour stay of the vote, so that we could do the work necessary to bring down the temperature and volatility, explain our positions and engage our communities,” she wrote. “That request was summarily dismissed.”