US President Donald Trump arrived in San Diego County, southern California, on Tuesday to survey the border wall prototypes he had commissioned, as around 100 protesters gathered on the US side of the border and security was ramped up on the Mexican side.
During the trip - his first to California since becoming President - Trump also claimed the State of California had been begging his administration to build walls.
He further slammed the Democrat for immigration and tax policy adding that while he thought Brown was a "nice guy" but "has not done the job".
"I have a message for you straight from the heart of the American people, and you know what that is".
"They can't climb some of these walls - some of them they can and those are the walls we aren't using", Trump said.
He said he had seen estimates that the "intolerably high" illegal immigration costs came to $100 billion a year in terms of drugs, crime, education and social services.More news: Mark Hughes early favourite to replace Mauricio Pellegrino at Southampton
Chanting "No ban! No wall!", demonstrators were cheered on by honking cars and buses at the San Ysidro port of entry in San Diego, the nation's busiest border crossing.
During his visit, Trump took aim at so-called "sanctuary cities" in California - local governments that refuse to cooperate with federal immigration officials seeking to deport illegal immigrants. It is his first visit as president to the state of California.
California has been at the forefront of resistance to the Republican leader's anti-immigration agenda and at odds with his stance on a number of other issues, from gun control to marijuana and the environment.
There are eight border wall designs.
The terminal is a few miles from the border-wall prototypes.
"California's sanctuary policies are illegal and unconstitutional and put the safety and security of our entire nation at risk".
He is expected to wrap up his day in Los Angeles with a fundraiser later in the evening. "The criminals take refuge in these sanctuary cities".More news: Chch Airport welcomes testing of autonomous air travel
Trump Tuesday tweeted about California's immigration policies as he flew to the state aboard Air Force One.
"You see, in California we are focusing on bridges, not walls", Brown wrote.
Trump has long said he wanted to visit the models himself so he can pick a victor, though the Department of Homeland Security says elements of each design are expected to be used.
His visit also sparked mass protests across San Diego, which has a huge Latin American community. Protests were also held on the Mexican side, in Tijuana.
Ahead of his arrival, the president tweeted that "thousands of unsafe, violent criminal aliens are released" as a result of California's immigration sanctuary policies.
After construction was completed, the prototypes were tested on several fronts, including on withstanding breaches, climbing, digging, their ability to slow down and stop border traffic, and whether they are safe for Border Patrol agents.
"When some people look at the U.S. -Mexico border, they see division", Faulconer said in his State of the City address in 2017.More news: Mattis Says Some Taliban Factions Might Be Interested In Peace Talks