Israel is launching a new ground offensive against Gaza.

The military claims it's targeting tunnels that allow terrorists to infiltrate Israel and carry out attacks. Hellfire missiles, drones and boots on the ground are all a part of the operation.

The offensive follows days of rocket fire from Hamas militants and retaliatory attacks from Israel.

The Gaza Strip is about 140 square miles and situated on Israel's southwestern border with Egypt. More than a million and a half people live there.

Also, the Obama administration says Israel must do more to prevent civilian casualties in Gaza.

State Department spokeswoman Jen Psaki on Thursday described as ``horrifying'' an Israeli attack a day earlier that killed four boys on a Gaza beach.

She said Israel must live up to its own standards of demanding that civilians not be targeted in the cross-border attacks.

More than 200 Palestinians have been killed in Gaza since Israel began launching airstrikes on the territory in response to hundreds of rocket attacks from Hamas militants and other Palestinian groups.

The U.S. has been pushing a plan for a cease fire that is being proposed by Egypt.