(CNN) -- U.S. law enforcement seized thousands of pounds of drugs and arrested hundreds of people in a synchronized bust targeting Mexican drug cartels and their associates, federal authorities said Friday.

The sweep involved several local, state and federal agencies, including the Drug Enforcement Administration and Immigration and Customs Enforcement, according to a statement from that organization.

Together, they arrested 676 people and seized more than $12 million, 282 weapons and 94 vehicles around the United States. In addition, nearly 40,000 pounds of marijuana, 467 kilograms of cocaine, 64 pounds of methamphetamine and 21 pounds of heroin were captured in the operation, the statement said.

John Morton, the immigration and customs agency's director, said the effort showed what U.S. law enforcement could do when working together on the issue, while stressing that its work wasn't complete.

"Through our continued coordination and cooperation with Mexican law enforcement, ICE agents and officers will strike at the very heart of these organizations by seizing the drugs, guns and money that fuel their criminal enterprises," Morton said.

The joint operation began Wednesday, roughly a week and a half after immigrations and customs' agent Jaime Zapata was ambushed on a highway while working in Mexico.

Drug Enforcement Administration spokesman Michael Sanders said the agencies are trying to send a message to cartel operatives in the United States. He described most of the targets as mid- to high-level dealers, the type who have day jobs but work in cells that distribute drugs and return drug money to Mexico.

A Houston police officer was shot Thursday as he tried to serve a narcotics warrant while taking part in the sweep. Officers returned fire, striking the suspect. The suspect's condition was unknown, police spokesman Kese Smith said.

Houston police officer Nash Patel was struck in the elbow and lower backside but was in good condition at the hospital, Smith said.

The people arrested this week belong to several cartels, Sanders said. The cells tend to be small and work in an isolated fashion, so it's possible that multiple cells from the same cartel may operate in the same city without knowing each other.

Those arrested could face federal drug charges or various state charges, depending on the evidence collected.

CNN's Mariano Castillo contributed to this report.