President Trump touring border wall prototypes in San Diego

Ultimately, the Trump administration expects that the whole border wall, when completed, would cost about $18 billion - though other estimates have ranged up to $38 billion.

The president also renewed his criticism of sanctuary jurisdictions - including those in California - saying they should be stripped of federal grant funding.

Trump's campaign pledge to build a massive wall along the border between the USA and Mexico has proven just as divisive outside Capitol Hill. "You have to know what's on the other side of the wall", adding that "you could be two feet away from a criminal cartel, and you don't even know they're there".

At least two protests and rallies planned at different locations today, with organizers making their plans based on expectations of where and when Trump will pass by.

About 10 miles (16 kilometers) west of the prototypes, protesters chanted, "No ban!"

President Donald Trump has arrived in San Diego, where he'll be touring the prototypes for his stalled border wall.

Trump's visit comes days after his Justice Department sued to block California laws created to protect people living in the US illegally.

Trump will visit eight towering prototypes for the wall before addressing Marines, also in San Diego, and attending a fundraiser in Los Angeles.

"The taxes are way, way out of whack, and people are going to start to move pretty soon", Trump predicted. "Congress must fund the BORDER WALL & prohibit grants to sanctuary jurisdictions that threaten the security of our country & the people of our country".

Faulconer, writing in The San Diego Union-Tribune, also said San Diego police work to protect everyone regardless of immigration status, an apparent dig at Trump's push to target illegal immigration.

Gov. Jerry Brown, a vocal Trump critic, tried to find common ground with the president. "Many of them were criminals with criminal records and very risky people".

The Republican brought a tough message on immigration to California during his first visit as USA president to the heavily Democratic state that has served as a base of resistance to many of his policies.

Trump wondered at the height of the mock ups, telling reporters that he envisions a tall wall preventing agile immigrants from entering the U.S.

Berkeley, Oakland and other cities have sought to stop doing business with firms involved with the wall, prompting the Associated General Contractors of America to ask Attorney General Jeff Sessions to sue to prevent states and localities from denying contracts or divesting from companies that participate in the barrier's construction.

The visit - Trump's first to the state as president - coincided with an escalating battle between his administration and the liberal state, which Democrat Hillary Clinton easily carried in the 2016 presidential election. Protests had already broken out there a day ahead of Trump's arrival and a similar scene of uproar could unfold later in the day when he arrives to Los Angeles.

Security is sure to be tight, although it is unknown to what extent Trump might expose himself in examining the prototypes.

The Justice Department last week sued to block a trio of California laws created to protect people living in the US illegally.

San Diego's city council a year ago passed a resolution opposing Trump's proposed wall.

President Trump inspected eight of border wall prototypes in San Diego while visiting California for the first time since taking office.

Trump on Tuesday is expected to be briefed on lessons learned from the construction of the prototypes built in San Diego last fall.

Trump has maintained that he expects Mexico to ultimately pay for the wall, perhaps as part of a renegotiation of the North American Free Trade Agreement.

Trump's visit comes just days after his Justice Department sued to block California laws created to protect people living in the US illegally.

Protests are also planned across the border in Tijuana, Mexico, as Trump examines the 30-foot-tall prototypes created to fulfill his signature campaign promise.

Ahead of the visit, a few dozen people gathered for a pro-Trump rally on the United States side of the border near the prototypes, while a similar number of the president's detractors came to the San Ysidro border post.