Initial reports from the other side seem to be implicating Hamas rockets for the explosion:

The IDF has not commented on the incident as of yet. The explosion was reported at the same time that heavy rocket barrages were fired from Gaza toward central Israel.
Rockets fired by Hamas and other Palestinian factions often fall short and hit buildings in Gaza, with dozens of deaths reported in such incidents in past rounds of conflict. During Operation Breaking Dawn in August 2022, two people were killed after a rocket fired from Gaza fell next to a clinic.
Hamas accused Israel of being responsible for the deaths, stating "We call on the international community and the Arab and Islamic countries to assume their responsibilities and intervene immediately now to stop the arrogance of the occupation and its fascist army."
https://www.jpost.com/breaking-news/article-768879

Waiting on more info. This is tragic no matter who is responsible.