The Democrat-controlled Congress is refusing to fund the project, the standoff leading to a partial government shutdown.
In Mexico, Central Americans hoping for asylum in the United States have been following the president's repeated calls for increased border security.
Al Jazeera's John Holman reports from Tijuana.
- Subscribe to our channel: http://aje.io/AJSubscribe
- Follow us on Twitter: https://twitter.com/AJEnglish
- Find us on Facebook: https://www.facebook.com/aljazeera
- Check our website: https://www.aljazeera.com/
#AlJazeeraEnglish #Trump #CaravanMigrants