Jerusalem, Oct 7 : Over 40 Israelis have been killed and more than 700 injured in the Hamas offensive that began earlier on Saturday. Besides, more than 50 Israelis have been reportedly held hostage by the militant group. The group published footage showing its members capturing a number of Israeli soldiers during an attack on a military base on the border with the Gaza Strip on Saturday. The Gaza-based terror group launched an unprecedented assault on Israel in the morning, firing thousands of rockets and sending gunmen into Israeli communities by land, sea and air, killing at least 40 people and injuring hundreds, The Times of Israel reported. The multi-pronged attack, coming a day after Israel marked the 50th anniversary of the surprise invasion on Yom Kippur, appeared to have caught the Israeli military and security forces completely by surprise. Hamas gunmen overran at least one military base and gunmen were moving through Israeli border communities, killing and capturing residents, apparently with little resistance from Israeli forces, residents were quoted as saying by the Israeli daily. Other clips circulated online have purported to show Israeli civilians taken hostage by the terror group. Arabic media claimed 52 Israelis had been captured. Some of those captured appeared to have been killed, the report said. After the surprise attack, Israeli Prime Minister Benjamin Netanyahu said the country "is at war", and vowed to exact an "unprecedented price from the terror group". "Citizens of Israel, we are at war. Not an operation, not a round (of fighting,) at war. This morning Hamas initiated a murderous surprise attack against the state of Israel and its citizens," Netanyahu said in a statement. /IANS