Where diplomacy fails, Israel says its tanks and troops are ready to stop militants in Gaza from firing missiles into Israel.
In scenes recalling the invasion of Gaza in the 2008-2009 winter, armour, artillery and infantry have been prepared along the Gaza border.
Prime Minister Benjamin Netanyahu has rejected criticism of his country’s response as confused and misplaced.
He said: “There is no moral symmetry, there is no moral equivalence between Israel and the terrorist organisations in Gaza. The terrorists are committing a double war crime: they fire at Israeli civilians and they hide behind Palestinian civilians – and by contrast Israel takes every measure to avoid civilian casualties.”
Taking every measure to avoid civilian casualties, however, is no comfort to the Palestinians.
Local officials said more than half the people killed in Gaza since air strikes began on Wednesday have been non-combatants.
Three years ago, the invasion caused 1,400 Palestinian deaths. As of 2 p.m. this Monday, the toll was approaching 100.
Rockets fired into southern Israel, not aimed at military targets, have killed three Israeli civilians.
Israel says its goal is to deplete Gaza arsenals and force the Hamas government to stop rocket fire that has hit Israeli border towns for years.
The rockets now have greater range.
Netanyahu’s deputy said if no more are fired at Israel’s citizens, if no attacks come from the Gaza Strip, Israel will not attack.
Khaled Meshaal, exiled leader of Hamas, the Islamist group that rules the coastal strip, said Israel had failed to achieve its objectives – said a truce was possible, but that Hamas would not accept Israeli demands until Israel stops its strikes and lift its blockade of the enclave.
A big rocket strike could be enough for Netanyahu to give a green light for a Gaza invasion, despite the political risks before a January vote that is expected to see him re-elected.
Hamas refuses to recognise Israel, and is sworn to destroy it, claiming all Israeli territory as Palestinian by right.