TUCSON, Arizona (AP) - Mexican law enforcement on Thursday crossed into Arizona by helicopter and fired two shots at U.S. border agents, a border patrol union leader says.
A Mexican law enforcement chopper crossed about 100 yards (92 meters) north into the Arizona desert, the U.S. Border Patrol said in a statement. The helicopter then fired two shots on the Tohono O'Odham Indian Nation, which sits on the border. Border patrol union leaders say the Mexicans fired at agents but that none of them were hurt.
However, Mexican authorities have denied shooting at agents and say they were under attack during a mission to find smugglers on the border.
The shots were fired at a time when border security has become a heated debate again as thousands of Central American immigrants, many of them unaccompanied minors or women with young children, have crossed through Mexico into Texas, overwhelming border agents who lack the resources to process so many people.
Tomás Zerón, the director of the Mexican attorney general's office investigative office, said that Mexican military and federal police who were conducting an operation on a ranch in Altar, Sonora, were shot at by criminals. Mexican authorities never fired any weapons and in fact never crossed into the U.S. side of the border, he said.
Art del Cueto, president of the local border patrol union, said four agents were in a marked patrol vehicle when they were shot at.
"They could say they didn't fire at the agents intentionally but for them to say that they were no shots fired within the United States, toward the United States Border Patrol, is a lie. They got in contact with our managers and apologized for the incident," del Cueto said.
The Mexican helicopter was 15 yards (14 meters) from the border agents when they were came under fire, Del Cueto said. He's also concerned that Tucson sector officials didn't notify the next shift of border agents that there had been a shooting, he said.
"... I think our managers within the area should have definitely informed the oncoming shift this had happened. We're always on high alert, but I think it would raise a fear level for our agents," del Cueto said.
Sebastián Galván, a spokesman for the Mexican Consulate in Tucson, said the office was gathering information but did not have any details yet.
This incident was not the first one in which the Mexican military has veered across the international boundary.
In January, U.S. border agents confronted two heavily armed Mexican soldiers who crossed 50 yards inside Arizona, the Los Angeles Times reported. A standoff ensued, but nobody was hurt.
In 2011, more than 30 uniformed Mexican soldiers in military vehicles crossed the Rio Grande without authorization in an incident that was believed to be inadvertent.
The FBI is investigating the incident.