Us begins construction of Mexico border wall prototype

Construction has begun on prototypes for Donald Trump's proposed border wall with Mexico, which was a key pledge of his presidential campaign. 

Eight models are to be built in a remote area of San Diego, four from solid concrete and four made of "other materials."

Both local and federal police have a heavy presence at the site, with a "free speech zone" set up nearby for people to demonstrate.

The US President had promised a "big, beautiful wall" at the border with Mexico.