BAGHDAD, Iraq - Shiite gunmen seized a police station Thursday in Najaf in the first outbreak of fighting since an agreement to end weeks of bloody clashes between U.S. troops and militia forces. Four Iraqis were killed and 13 were injured, hospital and militia officials said. Gunmen loyal to radical cleric Muqtada al-Sadr took control of the Ghari police station just 250 yards from the Imam Ali Shrine, witness Mohammed Hussein said. The station was looted and police cars were burned. "We sent a quick-reaction unit to assist the policemen defending the station, but they were overwhelmed by al-Sadr fighters,"...