Image copyright Getty Images Image caption Tens of thousands of people pass through the border crossing every day

California officials are warning of travel chaos over the weekend, as one of the largest land border crossings in the world closes for construction.

The San Ysidro Port of Entry - between San Diego, California and Tijuana, Mexico - will close to southbound travellers for 57 hours.

Pedestrian, tram, and bus crossings, as well as northbound car travel from Mexico, will not be affected.

Tens of thousands of people pass through the border every day.

The $741m (£546m) expansion project is expected to cause traffic delays until it is completed in 2019.

Media playback is unsupported on your device Media caption We travelled to the Mexican border city of Tijuana and asked everyday people one simple question: Where are you going?

The closure of southbound Interstate 5 and I-805 starts on Saturday at 03:00 (08:00GMT), and remains in effect until noon on Monday.

Vehicle travellers to Mexico have been advised to detour to the Otay Mesa Land crossing, about nine miles to the east, until the crossing reopens.

On any given day, San Ysidro processes an average of 50,000 northbound vehicles and 25,000 northbound pedestrians coming from Mexico.

The US General Services Administration decided to undertake the project after estimating an 87% increase in vehicle traffic by the year 2030.

It aims to realign the I-5 motorway where it connects to Mexico's El Chaparral Port of Entry, and double the number of vehicle inspection lanes.