On June 5, members of the Los Zetas drug cartel were crossing back into Mexico from the United States when they were spotted by a US Customs and Border Protection (UCSBP) helicopter along the Rio Grande river near Laredo.
The traffickers, who had recently delivered a shipment of drugs into the United States, opened fire with automatic weapons.
"The helicopter was impacted by gunfire, hitting the side of the aircraft and the rotor blade," a USCBP spokesperson told Tucson News Now last month. "The pilot was able to make a safe landing; there were no injuries."
The incident was an example of a rare, but not unprecedented, attack at a US-Mexico border that experts say is becoming increasingly porous.
The recent prison escape of Mexican drug kingpin El Chapo Guzman is expected re-energize drug cartel cells in Mexico that are battling the major Sinaloa drug cartel, Joel Vargas, of the international association InterPort Police, told the Washington Free Beacon.
"The partnership between the Gulf Cartel and Los Zetas, even with their own internal fighting going on, makes the border town of Laredo, Texas, a powder keg," Vargas said. "El Chapo will re-attempt to take back not only Laredo, Texas, but also consolidate control of El Paso, Texas."
A month after the US helicopter was forced down by gunfire, Mexican authorities killed six drug runners near Mexico's Nuevo Laredo, across the border from Laredo. The suspects had fired on and hit a Mexican Blackhawk helicopter carrying an armed convoy of suspected Zetas drug cartel members.
Like al Qaeda in the Middle East, the Zetas are well-armed and active on social media, according to US officials.
Authorities in Guatemala have captured M-16 and AK-47 rifles and grenades from Zetas operating there, the Free Beacon reported.
The group has posted to social media photos of beheaded rival gang members. It has also claimed responsibility for killing several bloggers who they say had exposed some Zetas.
Iran's Islamic Revolutionary Guards Quds Force, a paramilitary and covert action force, tried to recruit Zetas to conduct attacks against the United States. The Quds also has been seeking to work with Zetas to smuggle Afghan heroin into the country.
In 2011, the cartel took part in an Iranian plot to kill the Saudi ambassador to the United States. As a result of the failed scheme, the Obama administration placed a Quds commander on the list of designated terrorists.