In the largest assault on refugee camps since fighting between Israel and Palestinians began 17 months ago, Israel launched major attacks Thursday in what it says is an attempt to root out terrorists in the West Bank. The Israeli assaults with tanks, helicopters and troops targeted two camps, one in Balata near Nablus and another in Jenin. The Israel Defense Forces said the camps "are central bases for terrorist factors responsible for the murder of scores of Israeli civilians." The operations have resulted in the deaths of 10 Palestinians and one Israeli, according to the Israeli army and Palestinian security sources.