Two of the guns were reportedly used in the murder of a Border Patrol agent in December.
The Army said the six men and three women were working for the Zeta cartel. They said the gunmen mistook the agent's SUV for a rival drug gang.
Federal agents arrested eight people and seized three assault rifles, one shotgun, six handguns, about $40,000 and some marijuana in raids in San Diego.
"The ICE agents said we're Americans, we're diplomats. And the response from the Zetas was to open fire on the agents."
Three days ago, top Homeland Security Department officials touted new levels of cooperation with local law enforcement in a border task force. Now, one of the most prominent members of that task force has resigned, calling the government's announcement hypocrisy.
Prosecutors in the capital murder case say the defendant Shawna Forde formed a splinter group called Minuteman American Defense. Now she faces charges of first-degree murder.
Programs that help ex-cons reenter the workforce in risk of cuts.
A top federal official says his agency doesn't have enough staff to follow up on leads in gun cases or properly inspect guns shops.
Only serious offenders in Las Vegas Metro Police custody who are in the country illegally are put in deportation proceedings. What is the proper role of local police in federal immigration enforcement?
Hundreds of Border Patrol agents filled part of the baseball stadium in a sea of olive green. A line of riflemen stood at attention as the American flag and the agency's own flag fluttered in the cool morning air.