Israel reeled from its worst outbreak of communal violence in years as western and regional powers stepped up diplomatic efforts to end the conflict between Palestinian militants and Israeli forces. Violence between Israeli Jews and minority Israeli Arabs erupted in several Israeli towns, shaking the country to its core, and opening up a domestic front that led prime minister Benjamin Netanyahu to vow to quell rioting with “force, a lot of force”.

The rare outbreak of communal violence between Israeli citizens came as the fighting between Israel and Hamas, the Palestinian Islamist group that controls the hemmed-in Gaza Strip, entered its fourth day. Israel said three rockets were fired into northern Israel from Lebanon on Thursday, underlining the risk of yet another front opening up. The Israeli military said the rockets landed in the Mediterranean, causing no damage.

It was not clear who launched the rockets and Israel’s northern border with Lebanon has been quiet in recent months. Lebanon is home to Hizbollah, the powerful Iranian-backed movement that fought a month-long war with Israel in 2006, as well as Palestinian refugees and militants. A Lebanese army official said the situation about the rockets was still unclear. He dismissed local media reports that Palestinians had been arrested.

The UN peacekeeping force in Lebanon, Unifil, said Maj Gen Stefano Del Col, its head of mission, had spoken to the Lebanese army and Israel Defense Forces to urge de-escalation after this latest rocket attack. A spokesperson for Hizbollah did not immediately respond to a request for comment.

That attack came as Israel kept up its barrage of airstrikes against Palestinian militants in Gaza, raising the Palestinian death toll to 103, including 38 women and children, according to Palestinian health officials. A total of 580 have been wounded.

Hamas fired salvos of rockets deep into Israel on Thursday, causing Israeli authorities to reroute international flights from Tel Aviv. The militants have killed seven Israelis this week, including a soldier and a child.