Israel hit a Gaza school on Thursday in an airstrike that it said targeted and killed Hamas fighters inside.
Israel's military said its fighter jets had carried out a "precise strike" and circulated satellite photos highlighting two parts of a building where it said the fighters were based.
"We're very confident in the intelligence," military spokesperson Lt Col. Peter Lerner told a briefing with reporters, accusing Hamas and Islamic Jihad fighters of deliberately using U.N. facilities as operational bases.
He said 20-30 fighters were located in the compound, and many of them had been killed, but had no precise details as intelligence assessments were being carried out. "I'm not aware of any civilian casualties and I'd be very, very cautious of accepting anything that Hamas puts out," he said.
By Nidal al-Mughrabi, James Mackenzie, Antoine Khoury