Israel appeared to hold off on a threatened escalation of its week-old Gaza Strip barrage on Monday despite having balked at Western calls for a cease-fire with an equally defiant Hamas.

Israel's Army Radio said there had been "definite signals" that Gaza's dominant Hamas Islamists sought to tamp down the violence, though the report did not elaborate nor cite sources.

US Secretary of State John Kerry, whose bid to broker a wider peace deal collapsed in April when Israeli Prime Minister Benjamin Netanyahu called off negotiations with Western-backed Palestinian President Mahmoud Abbas over his surprise power-share with Hamas, offered on Sunday to help secure a Gaza truce.

The call was echoed by France and by Germany, which were scheduled to send their foreign ministers to the region on Monday. But with the US and European Union, like Israel, shunning Hamas as a terrorist group, Middle Eastern intermediaries were mooted.

A US official said that Kerry, in a phone conversation with Netanyahu, "described his engagement with leaders in the region to help to stop the rocket fire so calm can be restored and civilian casualties prevented, and underscored the US readiness to facilitate a cessation of hostilities, including a return to the November 2012 cease-fire agreement."

That referred to an Egyptian-mediated accord that doused the last big Gaza flare-up. Cairo is now again seeking calm. Hamas said it also received US overtures through Abbas and Qatar. Turkey has sought to intercede as well, Israeli media said.

Netanyahu's spokesman declined to discuss the conversation with Kerry. Another Israeli official played down the truce talk.

"We are not considering this-or-that proposal," the official, who declined to be named, said late on Sunday.

While allowing that a diplomatic solution could eventually be found, the official said Israel would, for now, pursue its military offensive "to restore quiet over a protracted period by inflicting significant damage to Hamas and the other terrorist groups in the Gaza Strip."

Hamas and Islamic Jihad, the second-most potent Gaza faction, made clear they would not accept a mere "calm for calm" where both Palestinian fighters and Israeli forces stand down.

"Netanyahu began this crazy war and he must end his war first," Hamas leader Izzat Al-Reshiq told Al-Arabiya television.

"There can be no cease-fire unless the conditions of the Resistance are met," he added, saying Israel had to stop blockading Gaza and free hundreds of Palestinians it rounded up in the occupied West Bank last month while searching for three Jewish seminary students who it said were kidnapped by Hamas.

On Monday, Israel said it shot down a drone from Gaza, the first reported deployment of an unmanned aircraft by Palestinian militants whose rocket attacks have been regularly intercepted.

More than 166 Palestinians, most of them civilians, have been killed, Gaza health officials said.