KAMPALA - Gunfire hit US military aircraft flying in to rescue people from fighting in South Sudan, wounding two US soldiers on Saturday, a Ugandan government official said.One plane was damaged when it was hit over remote Jonglei state, north of the capital and the scene of some of the worst clashes in almost a week of fighting in Africa's newest nation."Some American aircraft that had gone to rescue people (were) shot at," said the official, who did not want to be named.