A U.S. military base in San Antonio, Texas, issued an active shooter warning on Wednesday and ordered all personnel to implement lockdown procedures, according to a message on the facility’s official Twitter account. Emergency responders were working with the local police to locate more than one shooter at the Joint Base San Antonio Lackland and clear the area, officials said in a message posted to Facebook. It said no injuries had been reported in a shooting that appeared to have taken place outside a base gate. San Antonio Police had no comment and referred queries to Joint Base spokespersons, who could not be reached immediately. In 2016, two airmen were killed at Lackland in what military officials said was a “workplace violence incident.” The joint base, formed through a consolidation of two Air Force bases and the Army’s Fort Sam Houston in 2010, provides basic and advanced training to military …