Israel kills 30 civilians at shelter, witnesses tell U.N.

JERUSALEM (CNN) -- Israeli forces shelled a house where they had ordered about 100 Palestinian civilians to take shelter, killing about 30 people and wounding many more, witnesses told the U.N.

Israel Defense Forces said it is looking into the allegations.

"Credible eyewitness accounts" described the incident, which occurred in the volatile Gaza City suburb of Zeitoun, said Allegra Pacheco, deputy head of the U.N. Office for the Coordination of Humanitarian Affairs for the Palestinian territories. Pacheco spoke to CNN on Friday.

Witnesses reported that "about 100 civilians were evacuated" to a house Sunday, and the structure was shelled Monday, she said. The witnesses told the U.N. that two of the survivors said their children died.