JERUSALEM (Reuters) - Israel's Government Press Office on Saturday warned foreign journalists it was not responsible for their safety in the Gaza Strip, where the Jewish state has launched an offensive against Palestinian militants.

Israel sent ground forces into Hamas-dominated Gaza on Thursday after heavy air and naval barrages failed to stop rocket fire from the Palestinian territory.

Gaza officials said at least 335 Palestinians, many of them civilians, have been killed in the 12-day conflict.

"Gaza and its vicinity are a battleground. Covering the hostilities exposes journalists to life-threatening danger," an e-mailed Government Press Office (GPO) statement said. "Israel is not in any way responsible for injury or damage that may occur as a result of field reporting."

The GPO, which accredits journalists based in Israel, many of whom also cover events in the Palestinian Territories, charged Islamist group Hamas was using journalists as human shields and advised reporters to take "every possible precaution."

The Israeli military said that since the July offensive began, it has struck over 2,300 sites in the densely populated enclave and that more than 1,663 rockets have been launched by Palestinian militants toward its territory.

Its land incursion into Gaza has so far failed to subdue Hamas and its allies, who fired more than 90 rockets into Israel on Saturday, the Israeli army said.

Three Israeli soldiers and two civilians have been killed.