On his first visit to California since taking office, President Donald Trump examined border wall prototypes for his proposed project to restrict illegal immigration from Mexico.

As Trump stood by the eight prototypes in San Diego on the US border with Mexico, he said that some undocumented immigrants "are like professional mountain climbers", suggesting they would attempt to find a way over the wall.

California officials have sued the Trump administration 28 times on issues ranging from refugee and immigrant policy to environmental protection.

Meanwhile, a federal appeals court has upheld a ruling in the US state of Texas allowing police to ask people if they are in the country legally.

The law takes aim at so-called "sanctuary cities", which have been targeted by Trump for defying his immigration crackdown.

Al Jazeera's Rob Reynolds has more from San Diego, California.