Trump puts Immigration at the centre of his campaign
Media playback is unsupported on your device
Video

The view from a border agent on the US-Mexican border

Donald Trump has again used the issue of illegal immigrants crossing the US-Mexican border as a key piece of his election campaign.

Chris Harris, Border Patrol agent in the San Diego area, said illegal immigrants were crossing the border from a variety of countries. He spoke to Today special correspondent James Naughtie.