Video of the bombing:

GAZA CITY, Gaza Strip (AP) — An Israeli airstrike in Gaza killed three senior commanders of the Hamas military wing Thursday, delivering a likely blow to the organization’s morale and highlighting the long reach of Israel’s intelligence services.

The pre-dawn strike leveled a four-story house in a densely populated neighborhood of the southern town of Rafah, killing six people, including the three senior Hamas commanders.

The trio had played a key role in expanding Hamas’ military capabilities in recent years, including digging attack tunnels leading to Israel, training of fighters and smuggling of weapons to Gaza, Israel said.