Two Palestinian gunmen were killed Saturday while planting a bomb on the Gaza-Israel border, Palestinians and medical officials said. The men belonged to a militant offshoot of Fatah, the faction headed by Palestinian Authority Chairman Mahmoud Abbas. In a text message sent to reporters, the group said the two were on a "holy mission." An IDF spokeswoman said the two were shot after they ignored warning fire to leave the border area, where a security fence separates Israel