President Donald Trump used his first appearance in California as president on Tuesday to denounce the liberal state for refusing to cooperate with federal immigration authorities, saying the policy is the "best friend" of criminals.
Speaking later at California's Marine Corps Air Station, the President suggested there could be a "space force" akin to the country's air force.
Earlier in the day, Trump visited the border in California to look at various border wall prototypes.
Meanwhile, Trump himself - making his first visit as president to California, a state he has lambasted for not complying with his immigration laws - touched down to view the eight 30-foot-tall prototypes.
He also said "very soon we're going to Mars", adding "you wouldn't even be thinking about it" if Hillary Clinton had won the 2016 presidential election. "So you can be sure I'm going to use every power I have to stop them". "They don't tell you that, and we said no, we won't do it until we build the whole wall".
But James Schwab, who quit his job as regional spokesman for the US Immigration and Customs Enforcement department, said he believed the number was much lower.
During his trip to the border, Trump claimed "a part of San Diego needs a wall" in order to reestablish "law and order".
Trump's insistence that Mexico pay for the wall has soured relations and Mexican President Enrique Pena Nieto recently canceled plans to visit Washington amid continuing disagreement.
Trump is seeking $25 billion from Congress to extend the wall but Democratic leaders have balked.
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Trump's visit was greeted with peaceful protests by demonstrators both for and against his planned wall. While viewing the designs, Trump said he has a strong preference for a border wall that would allow law enforcement to see through into Mexico.
Trump was scheduled to give a speech to members of the military later on Tuesday before heading back to Washington. The president says the state's sanctuary policies are putting the country at risk. You have sanctuary cities where you have criminals living in the sanctuary cities.
He'll also address USA military personnel stationed near the border and attend the fundraiser in Los Angeles.
Trump Tuesday tweeted about California's immigration policies as he flew to the state aboard Air Force One.
At San Ysidro, Jose Gonzalez, 21, stopped to snap a photo of the protesters holding signs, including one that read: "Wall off Putin!" in reference to Russian President Vladimir Putin, who has a seemingly close relationship with Trump. Thousands of risky & violent criminal aliens are released as a result of sanctuary policies, set free to prey on innocent Americans.
On the other side of the border, in Tijuana, Mexico, residents laughed off the idea that the monolithic slabs will stop desperate immigrants. Jerry Brown, who said the Trump administration was "full of liars" and the lawsuit was akin to an "an act of war".
"People are so narrow-minded, " the Riverside firefighter said as the crowd chanted.
"It's not good", said Mauricio Villegas, 37, glancing toward the fence and prototype walls as he passed through on his way to a job at a veterinary office.