An Afghan government security guard opened fire Thursday on a group of foreign doctors at a Kabul hospital, killing three American physicians and wounding a U.S. nurse, officials said. According to its website, the Cure International Hospital was founded in 2005 by invitation of the Afghan Health Ministry. Mark Knecht, Cure International's chief financial officer, said outside the group's headquarters in Lemoyne, Pa., that it "remains committed to serve the people of Afghanistan." On April 4, an Afghan police officer shot two Associated Press journalists working in the eastern province of Khost, killing photographer Anja Niedringhaus and wounding veteran correspondent Kathy Gannon.