By Nidal al-Mughrabi and Michelle Nichols CAIRO/UNITED NATIONS (Reuters) -Israeli warplanes and tanks pounded southern Gaza overnight and on Tuesday, and the U.N. said aid distribution to Gazans facing growing hunger had largely stopped because of the intensity of fighting in the two-month-old war between Israel and Hamas. In the southern Gazan city of Rafah, which borders Egypt, health officials said 22 people including children were killed in an Israeli air strike on houses overnight. Civil emergency workers were searching for more victims under the rubble. Residents said the shelling of Raf…