GAZA, Aug 6 (Reuters) - Israeli aircraft struck in Gaza and Palestinian militants fired rockets at Israeli cities on Saturday as fighting ran into a second day, ending more than a year of relative calm along the border.

Israel on Friday said it had launched a special operation against the Palestinian Islamic Jihad militant group, killing one of its senior commanders in a surprise daytime air-strike on a high-rise building in Gaza City.

The Israeli strikes killed nine more Palestinians, including at least four Islamic Jihad militants and a child, and wounding 79 people, according to the Palestinian Health Ministry.

In the occupied West Bank, the Israeli military said it had apprehended 19 Islamic Jihad militants in overnight arrest raids.

Palestinian militants fired at least 160 rockets over the border, the military said, some deep into Israel toward the commercial hub Tel Aviv. Most of the missiles were intercepted and a few people were lightly injured when running to shelters.

Egypt, the United Nations and Qatar had begun mediating an end to the violence, according to a Palestinian official with knowledge of the efforts, "but no breakthrough yet", the official said.

A Western-backed Palestinian Authority official condemned Israel's attacks.

"We call on the international community to intervene and provide protection for our people," Civil Affairs Minister Hussein al-Sheikh said on Twitter.

Further escalation would largely depend on Hamas, the Islamic militant group which controls Gaza, and whether it would opt to join the fighting.

Tensions rose this week after Israeli forces arrested an Islamic Jihad commander in the West Bank, drawing threats of retaliation from the group.

Israeli Prime Minister Yair Lapid said Friday's strikes thwarted an immediate and concrete attack by Islamic Jihad.

The frontier had been largely quiet since May 2021, when 11 days of fierce fighting between Israel and militants left at least 250 people in Gaza and 13 in Israel dead.