California is deploying a first group of 224 National Guard troops to its southern border with Mexico to assist Border Patrol agents attempting to stem the flow of drugs and illegal immigrants.
"Today, our National Guard has been called to help secure the border and protect the safety of the American people," said Governor Arnold Schwarzenegger.
"I am proud that we are the first state to have our troops operational for this mission," he added at an event in San Diego, a border town some 200 kilometers south of Los Angeles which neigbhours the Mexican city of Tijuana.
Schwarzenegger stressed the deployment was not an alternative to a legislative solution to deal with illegal immigration, an issue President Barack Obama has been unable to tackle amid widespread opposition to immigration reform and amnesty for the millions of people in America illegally.
"We must find a permanent solution to our broken immigration system," he said.
"We need the federal government to step up with even more manpower and funding, and I will continue to push President Obama and Congress for action."
Obama last week signed legislation sending drones and an additional 1,500 new agents to the US border with Mexico, which runs across the states of California, Arizona, New Mexico and Texas.
The legislation also provides an additional 600 million dollars to combat drug, arms and people trafficking across the border.