Nearly 100 young children were evacuated from their preschool near Tel Aviv on Sunday when Arab construction workers at a neighboring building site began attacking their school by throwing rocks through the windows.

The 90 three- and four-year-olds were inside the preschool in Givatayim, a neighborhood on the fringes of Tel Aviv, when on Sunday morning two Arab workers from a nearby construction site went on the offensive, hurling rocks through an open kitchen window at the children and preschool staff members.

They also made vulgar gestures at the staff members, a parent of one of the children reported.

Staff quickly herded the kids out of the building into a nearby school. No injuries were reported, but when parents arrived to pick up their children, there were police units at the entrance, said one mother.

Police officers arrested two workers from the site, but both were released on bail after questioning. They were barred with a restraining order from entering Givatayim again.

One news site used the story as an opportunity to question Israel’s good-intentioned policy of allowing Palestinian Arabs, suffering from high unemployment in the Palestinian Authority, to enter and work in the country.

“Despite an influx of foreign aid…the Palestinian Authority have failed to create jobs for its people,” Israel Today wrote. “Israel has sought to alleviate the pressure that unemployment brings by allowing large numbers of Palestinian Arabs to enter its sovereign territory each day to work in construction.

“On Sunday, it was demonstrated how such gestures of goodwill can sometimes backfire.”