MEXICO CITY - Twenty-eight people were killed in a shootout among suspected rival drug gangs on a remote highway in the Mexican Pacific Coast state of Nayarit, authorities said.Police found 28 bodies strewn around 10 abandoned cars on a federal highway, Nayarit's state prosecutor's office said in a statement late on Wednesday. Four others were wounded.Officers found the crime scene after following up on a reported kidnapping, the statement said.