GAZA CITY, Gaza Strip - Israeli tanks and infantry backed by helicopter gunships have entered Gaza, launching a ground offensive that the military says will likely continue for several days.
The operation began after nightfall. Heavy gun battles are being reported and artillery fire has been hitting east of Gaza City where Hamas fighters were deployed.
In an interview on CNN, an Israeli military spokeswoman (Maj. Avital Leibovich) says there are "many, many targets," noting that Hamas has been digging smuggling tunnels and other facilities.
She says the aim is to take over areas used by militants to launch rockets against Israel and looks to be a "lengthy operation."
Hamas leaders have warned that they have prepared a violent welcome. They have also threatened to resume suicide attacks inside Israel.
Israel's offensive began with a week of aerial bombardment that's claimed more than 460 Palestinians lives. But that has not stopped Hamas from firing into Israeli border towns, where four people have been killed.