is not the time to back down. >> my view of the israeli operation, stay as long as you need to stay, go wherever you need to go to deal with the viper's nest called hamas. >> nbc's martin fletcher is live for us in tel aviv with the very latest. martin, give some insight of what the feeling is over there. obviously now casualties starting to mount against the israeli military has to weigh heavily on the hearts and minds of israelis. >> reporter: well, yeah, luke, they do weigh heavily. on the other hand they don't provide any impetus to stop the fighting. if anything, as you just pointed out in the last sound bite, the push here is to increase the fighting. there are so many casualties, suddenly the worst israeli death toll since 2006 in the military. 13 dead yesterday. by the way, that may rise today. there was an infiltration by hamas gunmen through a tunnel