A Federal policeman searches a man for weapons and drugs at a checkpoint in the border city of Rio Bravo, in the northeastern state of Tamaulipas, January 9, 2008. Federal troops have increased their presence after two federal policemen were gunned down on Tuesday in a shootout with suspected drug gang hitmen in the border city of Reynosa. In 2007, more than 2,500 people were killed nationwide in drug-related murders despite the military clampdown on traffickers. REUTERS/Tomas Bravo (MEXICO)