US authorities closed the San Ysidro border in Tijuana for at least 30 minutes on Thursday in a practice exercise designed to ward off the thousands of migrants who began amassing near the pedestrian crossing.
The closure affected only vehicle traffic moving towards the US. Army members were present, but were not called upon during the exercises.
At the same time many migrants decided to stage an indefinite sit-down at the entrance to the border bridge, thus hoping to exert pressure on US immigration authorities over their asylum application.
The migrants were closely managed by Mexican police to prevent any illegal crossings.
The situation along the border remains tense. US President Donald Trump has vowed to prevent the migrant caravan from entering the country and instead chose to bolster border security.
The migrants, mostly fleeing violence and poverty, have been travelling for over a month after the group first formed in San Pedro Sula, Honduras.