The Gateway International Bridge in Brownsville was temporarily closed Tuesday as several agencies prepared for the end of Title 42.

U.S. Customs and Border Protection — along with the members of the National Guard, the Texas Department of Public Safety and Brownsville Border Patrol agents participated in the half-hour-long training exercise for what they say could happen once the policy ends.

In a statement, CBP said they hold these types of exercises periodically to prepare for disturbances and mass migration attempts.

The sounds of warnings and explosive simulators added to the sight of dozens of officers with weapons in one hand, and shields in another.

The training occurred after an estimated 15,000 migrants crossed into the U.S. illegally through Brownsville last week.

RELATED: Large group of migrants continues moving through Brownsville

Many of the migrants said they are looking for a better opportunity. 

Venezuelan migrant Jeancarlos Sáez, crossed into Brownsville through the port of entry, and his life is now a waiting game

“We have to wait because until the people in charge give us more information, we really don't have an option,” Sáez said. 

Title 42 is set to end on Thursday, May 11.