At least 20 Palestinians were killed in Israeli strikes on the Gaza Strip overnight and into Saturday, according to local health officials. The 20-month war with Hamas has raged on even as Israel has opened a new front with heavy strikes on Iran that sparked retaliatory drone and missile attacks.

Israel's strikes overnight on Friday targeted Iran's nuclear facilities, ballistic missile factories, military commanders and nuclear scientists. Israel's Prime Minister Benjamin Netanyahu said it was the start of a prolonged operation to prevent Tehran from building an atomic weapon.

Years of intelligence collection, infiltration of Iran with commandos and weapons, and tracking of targeted commanders and scientists made the wide-ranging attacks possible.