Nine children were among the 24 killed from airstrikes launched by Israel on Gaza early Tuesday that hit the high-rise home of a Hamas field commander and two border tunnels dug by militants, as Hamas and other armed groups fired dozens of rockets toward Israel.

Since sundown Monday when the cross-border fighting erupted, 24 Palestinians – including nine children – were killed in Gaza, most by airstrikes, Gaza health officials said. The Israeli military said 15 of the dead were militants. During the same period, Gaza militants fired more than 200 rockets toward Israel, injuring six Israeli civilians in a direct hit on an apartment building.

This was preceded by hours of clashes Monday between Palestinians and Israeli security forces, mainly in Jerusalem but also across the West Bank. More than 700 Palestinians were hurt, including nearly 500 who were treated at hospitals.

In a sign of widening unrest, hundreds of residents of Arab communities across Israel staged overnight demonstrations against the situation in Jerusalem, one of the largest protests by Palestinian citizens in Israel in recent years.

The current violence, like previous rounds, was fueled by conflicting claims over Jerusalem, home to major holy sites of Islam, Judaism and Christianity. The rival national and religious narratives of Israelis and Palestinians are rooted in the city, making it the emotional core of their long conflict.

In the past, cross-border fighting between Israel and Hamas, the group that rules Gaza, would typically end after a few days, often helped by behind-the-scenes mediation by Qatar, Egypt and others. It was not clear if that trajectory would be repeated this time.

Israeli Prime Minister Benjamin Netanyahu warned Monday that fighting could “continue for some time.” Lt. Col. Jonathan Conricus, an Israeli military spokesman, told reporters Tuesday that the military was in “the early stages” of strikes against Gaza targets it had planned well in advance.