More asylum seekers arrive at border as US expands military power

Migrants and refugees continue long wait in Tijuana as US defence chief given extra authority to use military at border.

The American troops on the southern border with Mexico could be given permission to use lethal force, if necessary, to protect customs officials.

Thousands of asylum seekers are gathering near the border – after making their way from Central America.

Al Jazeera’s John Holman reports from Tijuana.