The party leadership vowed there would be no interruption in funding, with the cash being sourced elsewhere -- but not before being berated by Republicans for capitulating to "anti-Semites" on their left flank.

While the row looked ultimately like a storm in a tea cup, it underlined that progressives are becoming increasingly skeptical of no-strings-attached aid to America's key ally in the Middle East, just months after the end of hardline right-winger Benjamin Netanyahu's 11-year premiership.

Operational for a decade, Iron Dome has intercepted and destroyed thousands of short-range rockets and artillery shells launched by Hamas militants from Gaza before they were able to hit populated areas, Israeli officials say.

Tuesday's drama was sparked by House Democrats removing a provision originally included in a bill to keep the federal government funded that would have helped boost the Israeli air defense system.

The about-face came after a group of leftist representatives objected to the allocation, US media reported, threatening to tank the bill when it comes up for a vote later Tuesday.

House Appropriations chair Rosa DeLauro said there would be no interruption in funding for the Iron Dome, Politico reported, giving assurances that it would be in the defense budget for the 2022 fiscal year.

House Republican leader Kevin McCarthy blasted Democrats for capitulating to "the anti-Semitic influence of their radical members," an accusation echoed by conservative Texas Senator Ted Cruz, who urged the Democratic rank-and-file to denounce the party's leadership.

Dean Phillips, a Democratic congressman from Minnesota, tweeted he was "incredulous" that colleagues would risk shutting down the government rather than defend "one of our most important allies and only Jewish nation in the world" from Hamas rockets.