International leaders condemned an unprecedented incursion by Palestinian militants into southern Israel, while governments across the Middle East called for restraint after an attack that shook the Israeli security establishment.

“This attack is having a horrific impact on Israeli civilians,” the UN high commissioner for human rights, Volker Türk, said in a statement, calling on Israel to avoid civilian casualties in its response.

“Civilians must never be the target of attack,” he said.

Israel responded by attacking the Gaza Strip, leaving at least 198 people dead and almost 2,000 wounded, according to the health ministry.

Stéphane Dujarric, the spokesperson for the UN secretary general, said António Guterres was “deeply concerned for the civilian population and urges maximum restraint”.