The IDF said Tuesday that a hospital blast which reportedly claimed the lives of hundreds of civilians earlier in the day was caused by a misfired rocket launched by the Palestinian Islamic Jihad (PIJ), a terrorist group operating within the Gaza Strip.

“According to intelligence information, from several sources we have, the PIJ organization is responsible for the failed [rocket] fire that hit the hospital,” the IDF said in a statement. According to the Israeli military’s analysis of “operational systems, an enemy rocket barrage was carried out towards Israel, which passed in the vicinity of the hospital, when it was hit,” the statement added.

The Palestinian Ministry of Health, a government body under the control of Hamas, previously claimed that an Israeli air strike was responsible for the hospital explosion. The ministry said that an estimated 500 civilians were killed in the blast.