Israel was facing widespread international condemnation yesterday for its onslaught in Gaza, as the UN and EU demanded an end to a "disproportionate" response to Palestinian rocket attacks, which were also denounced. Israel's prime minister, Ehud Olmert, rejected the criticism and vowed to press on with the offensive, which has claimed an estimated 100 Palestinian lives in the past five days.

Early today, after clashing with militants and making arrests yesterday, Israel moved more troops into northern Gaza and five Hamas militants were killed in nine airstrikes.

On Saturday alone, some 60 people were killed, the biggest Palestinian casualty toll since the second intifada broke out more than seven years ago. "Nothing will prevent us from continuing operations to protect our citizens," Olmert said. Two Israeli soldiers and one civilian have also been killed in the violence.

Human casualties apart, western governments expressed alarm at the decision by Mahmoud Abbas, the Palestinian president and bitter rival of the Hamas Islamists in Gaza, to freeze all contacts with Israel, putting the already moribund peace process at greater risk. Saeb Erekat, the chief Palestinian negotiator, said: "For the time being, negotiations are suspended because we have so many funerals."

Britain reacted by calling on Palestinians and Israelis to "step back from the brink". David Miliband, the foreign secretary, said: "Israel's right to security and self-defence is clear and must be reiterated and supported. But measures taken in response to rockets must be in accordance with international law, minimising the suffering for innocent civilians and maximising the scope for political negotiations to be restarted."

With Condoleezza Rice, the US secretary of state, due in Jerusalem tomorrow, a White House spokesman said: "The violence needs to stop and the talks need to resume."

Arab states were united in outrage. Pro-western Jordan, which, like Egypt, has a peace treaty with Israel, called the Gaza operations a "flagrant violation" of international law. Saudi Arabia, which brokered last year's revived Arab initiative backing peace with Israel, condemned what it called "mass killings".

In Rome, Pope Benedict told pilgrims and tourists in St Peter's Square: "Only by showing absolute respect for human life, even if it is that of the enemy, can one hope to give a future of peace and coexistence to both of those peoples who have their roots in the Holy Land."

Hamas faced direct criticism too. On Saturday, after an emergency UN security council session convened by Libya expressed "deep concern" at the fighting, the UN secretary general, Ban Ki-moon, bracketed condemnation of Israel's response to Palestinian rocket fire with a denunciation of the Hamas missile attacks on Israeli towns.

"While recognising Israel's right to defend itself, I condemn the disproportionate and excessive use of force that has killed and injured so many civilians," he said. "I condemn Palestinian rocket attacks and call for the immediate cessation of such acts of terrorism."

Israel's deputy UN ambassador, Daniel Carmon, blamed Iran and Syria for "sitting behind the scenes, orchestrating and supporting Hamas terrorism against Israel".

The EU yesterday issued a similar statement to the UN, as the union's foreign policy chief, Javier Solana, began a visit to Israel, the Palestinian territories and Lebanon. "Words are not enough", admitted the EU special Middle East envoy, Marc Otte. "We need to encourage the parties to look at another way to resolve the situation." The EU, like the US, has supported Israel's refusal to negotiate with Hamas since it won the 2006 Palestinian elections and then took over Gaza last summer.

In south Lebanon, hundreds of supporters of the Shia movement Hizbullah gathered on the border with Israel, waving banners and shouting "Death to Israel". Demonstrations were also held in Palestinian refugee camps in Syria, Jordan and Lebanon. In Egypt, thousands of university students protested.

Turkey, Israel's closest ally in the Muslim world, said the Gaza operations were killing "children and civilians" and had "no humanitarian justification".

© 2008 The Guardian