IDF Chief of General Staff Lt. -Gen. Gabi Ashkenazi said Tuesday that Hamas terrorists were attempting to attack IDF troops while wearing IDF uniforms. Speaking at the Knesset's Foreign Affairs and Defense Committee, Ashkenazi also said that the military had identified and demolished many buildings where tunnel exits were located. Channel 2 reported that one of the tunnels already had an opening on its Israeli side, complete with ladders and staircases, and that its discovery at the last minute had prevented a terror attack. One Palestinian was killed inside the tunnel as it was demolished. "Hamas has been badly hit, in terms of losses in manpower including some top commanders, and also in terms of property, infrastructure, weapons caches and staging areas. Our forces continue to operate in the theater and hit the military wing of Hamas," Ashkenazi said. "Fighting is taking place in an urban area, densely built and densely populated. Hamas is firing at our forces and we are firing back. An urban area - this is the theater in which our soldiers fight and this is where the toll of civilian casualties is likely to occur." The IDF's top general went on to say that Hamas was using the Gaza Strip's non-combatants as human shields. "In many cases Hamas forcefully prevents civilians from leaving the area. The IDF is very careful not to hurt civilians. For this purpose hundreds of thousands of leaflets were dropped from the air, television broadcasts were made, tens of thousands of telephone calls were made to houses which, according to intelligence, were being used to store and manufacture weapons, so that their inhabitants could leave before the [IDF] attacks." Ashkenazi said there was no doubt Iran was backing Hamas financially and technologically, as well as supplying arms to the terror group. According to IDF estimates, close to 950 Palestinians have been killed since Operation Cast Lead began in late December. Based on intelligence and information obtained by the Gaza Coordination and Liaison Administration, the IDF has determined that close to 450 of those killed were known Hamas operatives. The IDF further believes that among the remaining 500, a significant number are also Hamas operatives. In addition, the IDF believes that there are a number of Hamas fighters buried under rubble throughout northern Gaza. One Armored Brigade officer said that there were many cases when the IDF destroyed tunnels near homes and that the blast then demolished the home that it was connected to even if the distance between the opening of the tunnel and the home was 100 meters. Since the operation began, 2,310 IAF sorties were made, 1,114 "targets of opportunity" were taken out and 26 targets which were symbols of Hamas rule were destroyed.