THE DEPARTMENT OF DEFENSE has quietly signed a $210 million deal to buy advanced cluster shells from one of Israel’s state-owned arms companies, marking unusually large new commitments to a class of weapons and an Israeli defense establishment both widely condemned for their indiscriminate killing of civilians.

The deal, signed in September and not previously reported, is the department’s largest contract to purchase weapons from an Israeli company in available records, according to an online federal database that covers the last 18 years. In a reversal of the more commonly seen direction for weapons transfers between the countries — in which the U.S. sends its weapons to Israel — the U.S. will pay the Israeli weapons firm Tomer over a period of three years to produce a new 155mm munition. The shells are designed to replace decades-old and often defective cluster shells that left live explosives scattered across Vietnam, Laos, Iraq, and other nations.

The terror of cluster weapons persists long after the guns that fired them have quieted, as civilians return to fields, forests, and settlements laced with bomblets that can explode years later without warning.

“The footprint of the injuries of these weapons is so horrifying,” said Alma Taslidžan, advocacy manager for the aid organization Humanity & Inclusion, which pushes to ban cluster munitions. She recalled speaking with a 17-year-old boy who found an unexploded cluster bomblet in his neighbor’s garden in the aftermath of the Bosnian War.

“He said he played with it for quite a while. Suddenly it exploded. It blew up both of his hands; it blew away part of his face as well,” she said.