President Donald Trump has inspected several proposed models for a border wall to separate the United States and Mexico.
Trump went to the border site Tuesday, just after landing in San Diego. It is his first visit as president to the state of California.
The president spoke to reporters and others gathered at the site. He said a new wall would help stop ''99 percent'' of illegal immigration or, in his words, ''maybe more than that.''
There are eight border wall designs. Trump said he favored a fully concrete wall because it was the hardest to climb. However, he also noted part of the wall should be transparent.
Trump said he noticed the repaired holes in some parts of the existing fence at the border. He described the existing wall as "lousy" but noted it stopped as much as 95 percent of attempted illegal entry.
Activists for and against the president's plan demonstrated near the site. The Trump administration is currently battling with California about its refusal to help federal agents detain undocumented immigrants in the United States.
The president said Tuesday that the state's sanctuary policies ''put the entire nation at risk.'' Last week, the U.S. Justice Department took legal action against California over three state immigration laws.
Trump said the laws were the best friend of the criminal. ''The criminals take refuge in these sanctuary cities and it's very dangerous for our police and enforcement folks,'' he said.
While in California, Trump is also expected to speak to Marines in San Diego. He will also attend a fundraiser in Los Angeles, where he will stay overnight.
Demonstrations were held at the San Ysidro port of entry in San Diego, the nation's busiest border crossing, where protesters chanted, ''No ban! No wall!'' Protests were also held on the Mexican side, in Tijuana.
At San Ysidro, 21-year-old Jose Gonzalez expressed his displeasure with Trump's policy.
''I don't think it's really fair how he has the choice to separate us,'' he said. Gonzalez holds Mexican and U.S. citizenship. He crosses the border from Mexico daily to work at a San Diego restaurant.
However, 48-year-old Army veteran Mark Prieto criticized the protesters.
''People are so narrow-minded,'' the Riverside firefighter said as the crowd chanted. ''Finally we have someone who is putting America first.''
His wife, Corina Prieto, a nurse who has extended family in Mexico, agreed. Both voted for Trump.
''I think he is doing a lot of good, like protecting our Border Patrol,'' she said.
I'm Caty Weaver.
Caty Weaver adapted the story for Learning English based on AP news reports. Hai Do was the editor.