U.S. Defense Secretary Donald H. Rumsfeld (search) said Wednesday that reports of Venezuela's efforts to purchase 100,000 Kalashnikov assault rifles from Russia were troubling, suggesting the South American country has no need for so many weapons.

"I can't understand why Venezuela (search) needs 100,000 AK-47s (search)," he said during a press conference with Brazil's Vice President and Defense Minister Jose Alencar. "I personally hope it doesn't happen. I can't imagine if it did happen it would be good for the hemisphere."

American officials in Washington have expressed concern about the health of democracy under Venezuelan President Hugo Chavez (search), his stance toward leftist Colombian rebels and his moves to buy helicopters and Kalashnikov rifles from Russia.

Although Rumsfeld and Alencar praised U.S. and Brazilian cooperation on a number of issues, fractures were apparent: Alencar refused to directly criticize Venezuela or the Revolutionary Armed Forces of Colombia (search) (FARC), which the United States considers a terrorist organization but Brazil does not.

Asked whether Brazil would consider FARC a terrorist organization, Alencar said through a translator, "From a distance, we cannot make a final judgment with respect to this question. However, if the organization adopts crime as an instrument for raising resources, obviously, it is injurious."

Rumsfeld also met with Brazilian President Luiz Inacio Lula da Silva (search) and then was to fly to the jungle city Manaus to view what the Brazilians call "SIVAM" — or Amazon Surveillance System (search) — a powerful array of radars and other sensors, networked to monitor both criminal activity and environmental conditions in the Amazon, the world's largest wilderness.

Rumsfeld has pushed for countries to assert control over remote areas within their borders, arguing that criminal and terrorist elements could flourish in the absence of a government presence.

Drug flights over the area covered by the network have been reduced by 30 percent since it went online, according to a senior U.S. defense official, who spoke on the condition of anonymity.

The $1.4 billion network of airborne and ground-based radars and computers can also monitor illegal landing strips and climatic conditions in some of the 2 million square miles of jungle that comprises the Amazon.

SIVAM was built by U.S. defense contractor Raytheon Corp. (search) Critics have argued it focuses too much on security issues and not enough on regions where illegal logging and other environmental damage takes place.

Rumsfeld was to fly to Guatemala later Wednesday.