Hamas’s indiscriminate rocket fire aimed at Israel this spring amounted to a war crime because they targeted civilian areas, Human Rights Watch announced on Thursday.

Hamas, the Gaza-based U.S.-designated foreign terrorist organization, launched thousands of rockets at Israel during a flare-up of tension in May that lasted about two weeks. While a significant majority of the rockets aimed at Israel were intercepted by the Iron Dome, their missile rocket-intercepting system, Israel launched their own strikes, targeting Hamas but also killing civilians nonetheless.