Israel's Threat As Thousands Flee Northern Gaza

Israel has appeared to hold off on a threatened escalation of its Gaza Strip offensive, but Palestinian deaths continue to mount.

On Sunday, the Israeli military warned residents of the northern border town of Beit Lahiya to leave or risk their lives when, after nightfall, it planned to intensify air strikes against suspected Palestinian rocket launchers among civilian homes.

But despite a lone strike on farmland outside the town there has been little sign so far of the Israeli operation being ramped up.

However, Israeli troops launched a ground operation in the northern Gaza Strip, the first since the offensive against Hamas began.

The navy commandos' brief incursion on Sunday - which ignored a United Nations call for a ceasefire - targeted a rocket launcher site, according to Israeli public radio.

The armed branch of Hamas confirmed that Israeli troops had exchanged gunfire with Palestinian fighters.

Thousands of residents in northern Gaza have fled their homes, after the Israeli military warning.

Prime Minister Benjamin Netanyahu said the military would be hitting Hamas "with growing force," warning there was no end in sight. 

"We do not know when this operation will end," he told ministers.

In an interview on CBS's Face the Nation, he defended the offensive.

"When we began this interview we were under bomb alert and as the minutes passed now we're told people can go out into the open air again," he said.

"This is the kind of reality we're living in. And we'll do whatever is necessary to put an end to it."

Mr Netanyahu urged Americans to imagine US cities from the East Coast to Colorado, or 80% of the population, were under threat of rocket attack, with only 60 to 90 seconds to reach a bomb shelter.

"That's what we're experiencing right now, as we speak," he said.

US Secretary of State John Kerry has phoned Mr Netanyahu to renew a US offer to help mediate a truce.

Palestinian President Mahmoud Abbas is to ask the United Nations for international protection as the offensive continues.

Israel began its offensive on Tuesday in response to weeks of rocket attacks from Hamas militants in Gaza, who are understood to have fired more than 600 missiles into the country.

Two more rockets shot from Gaza were destroyed over the Tel Aviv area by the Iron Dome missile defence system on Sunday, several hours after another two rockets were intercepted over Lod, close to the country's main airport.

Hamas has denied being behind a rocket attack on Israel from Lebanon on Saturday evening.

A rocket fired from Syria hit the Golan Heights, falling on open ground and causing no casualties, an army spokeswoman told AFP.

Earlier that day an Israeli warplane bombed the home of Gaza's police chief and damaged a nearby mosque, killing at least 18 people and wounding 50.

It was the deadliest single attack during the conflict, which has now claimed 165 Palestinian lives and left more than 1,000 injured.

No Israelis have died so far in the latest conflict, and many of the rockets fired into the country have been intercepted by Iron Dome.