JERUSALEM, Israel -- A school bus carrying Palestinian Arab children collided with a truck north of Jerusalem Thursday morning, killing seven kindergarten children, a teacher and injuring scores of others, some critically.

The bus was transporting the children to an outing at a park near Ramallah when the head-on collision caused the bus to flip on its side and catch on fire.

Magen David Adom, Israel's national rescue service, declared the accident a "mass casualty event."

Police, firemen and emergency rescue personnel from MDA and the Red Crescent, the Palestinian Authority's rescue service, were working together at the scene.

Most of the critically injured children were transported to Hadassah Hospital's two Jerusalem locations in Mount Scopus and Ein Kerem.

Israeli and Palestinian police are conducting a joint investigation.