Why do the Israeli forces threaten to carry out a massive offensive against the Palestinians?

Israeli-Israeli troops have besieged the Palestinian National Authority headquarters in Ramallah, the first military operation in this region since last November. Twenty armed vehicles and jeeps took part in the operation. Israeli forces have been threatening to carry out a massive offensive against the Palestinians after a suicide attack in the Kami crossing that killed six Israelis.
Question: Why do the Israeli forces threaten to carry out a massive offensive against the Palestinians?

The United States military says an American airstrike has killed five militants in Iraq. The military said the militants were burying a bomb along a road in the city of Diwaniyah. A military spokesman says another militant survived the attack.
Question: How many militants were killed in the airstrike?