New York: Israeli attacks on three schools run by the United Nations in the Gaza Strip in the last 24 hours, including one that killed more than 46 civilians Tuesday, were "totally unacceptable and must not be repeated," UN Secretary General Ban Ki-moon said.

The three schools were operated by the UN Relief and Works Agency for Palestinian Refugees in the Near East (UNRWA) in Gaza. The UN said about 15,000 Palestinians, who fled the fighting between Israel and Hamas, had found refuge in these schools as well as in more than 20 other schools in the territory.

Ban said in a statement that the locations of the schools had been given to the Israeli army and Israel was warned that its operations were endangering UN compounds.

"I am deeply dismayed that despite these repeated efforts, today's tragedies have ensued," Ban said. "These attacks by Israeli military forces which endanger UN facilities acting as places of refuge are totally unacceptable and must not be repeated."

"Equally unacceptable are any actions by militants, which endanger the Palestinian civilian population," he said. "Today's events underscore the dangers inherent in the continuation and escalation of this conflict. I call once again for an immediate ceasefire."

Israel said Tuesday that Hamas militants fired mortars from the UN school in northern Gaza, which was shelled by Israel, killing more than 46 civilians, according to a military spokesman in Tel Aviv.

He said Israeli ground troops stationed on the outskirts of the Jabaliya refugee camp responded by firing mortar shells in the direction of the militants.

"This is not the first time that Palestinian militants have fired from within UN schools," he said.

Source : IANS