Mexico says citizen shot by US Border Patrol agent near Texas MEXICO CITY - A Mexican citizen has been fatally shot by U.S. Border Patrol agents on the border with Texas in an incident that the Mexican government is calling a disproportionate use of force. The Border Patrol said Saturday that agents had opened fire along the Rio Grande on the Texas-Mexico border after being pelted by rocks and having a gunman point a weapon in their direction from the Mexican side of the river. The agency said it did not know if anyone else was hurt, but the FBI was investigating. The Mexican Foreign Ministry said late Sunday that a citizen had been killed by a gunshot fired by a U.S. agent at the Los Tomates-Veterans international bridge. It did not identify the victim or provide details about the incident. Mexico said its consulate in Brownsville had sent U.S. authorities a message demanding an exhaustive investigation without regard to the consequences. "The Mexican government has said once again that the disproportionate use of force for purposes of immigration enforcement is unacceptable under any circumstances," the Foreign Ministry said. Border Patrol spokesman Henry Mendiola said several people had been taken into custody but that he could not provide details about the suspects or charges they face. One of the agents started shooting after being "unable to take cover" when rocks were thrown, while the other opened fire after seeing a suspect on the Mexican side of the river pointing a gun at him, Mendiola said. He added that as rocks were thrown, "at least one of the agents feared for his life." The Border Patrol released few other details about the incident, including what the suspects were doing along the river. Border Patrol agents seizing 4,000 pounds of marijuana in March got into a shootout with drug smugglers. In that incident, it also was not known whether anyone on the Mexican side was hit. Last summer, authorities said Border Patrol agents and rangers with the Texas Department of Public Safety exchanged about 300 rounds of gunfire with suspected drug smugglers. Officials said the suspects threw rocks at U.S. lawmen in that incident, too. In 2010, a Border Patrol agent in El Paso shot and killed a 15-year-old Mexican boy across the Rio Grande. Investigators say the agent fired after being attacked by people throwing rocks.