Israel says Gaza invasion will be limited

GAZA CITY -- The streets of Gaza were a ghost town Friday. Nobody could be seen or heard -- just thuds of incoming airstrikes and the roar of outgoing rockets.

After sending its soldiers across the border and into the Gaza Strip Thursday night, Israel said its invasion would be a limited offensive, not an occupation, and that it was aimed mainly at destroying tunnels used by Palestinian militants to infiltrate Israeli territory, reports CBS News' Holly Williams.

The Israeli military claimed it foiled an attack early Thursday by 13 heavily armed militants using one of the tunnels. Israel's government said it was that attack -- and rocket fire by militants during what was supposed to be a brief humanitarian ceasefire Thursday morning -- that forced it to act to defend its own citizens.

The first sign that a ground invasion was imminent was a night of heavy bombardment from the air, clearing the way for Israeli troops and tanks.

Even before the ground offensive began, more than 240 Palestinians had been killed in 10 days of airstrikes. Officials in Gaza say most of them were civilians.

On Thursday, even before the Israeli offensive kicked off, three more Palestinian children were killed when a shell hit their home.

"Suddenly, a rocket came from above and hit their roof," said their neighbor. "We carried them in our arms."

Palestinian militants have fired more than 1,300 rockets into southern Israel during this escalation, killing one person and causing injury and damage. But many of the rockets are shot down by Israel's "Iron Dome" anti-missile defense system.

So far, Israeli troops have only moved into the northern Gaza Strip, and it wasn't clear whether they were going to push any further south, but the airstrikes continued unabated.