NABLUS, May 3, 2004, (WAFA) –Israeli Occupation Forces (IOF) tightened Monday its already-imposed military closure on Nablus City, isolating it completely from the outer world, Palestinian security sources said.... They confirmed that the IOF blocked Hawarra checkpoint, south of the city, denying the civilians’ access from - into it. They also denied the Palestinian ambulances’ access from into the city.... In another incident, the IOF troops, stationed at Rojeeb checkpoint, denied trucks loaded with food supplies access into the city, witnesses said.... They confirmed that a total strike spread allover the city protesting against the yesterday killing of four citizens by Israeli combating helicopters which fired a number of missiles against their car driving in Nablus City....