The United States government is now tracking a third migrant caravan making its way north from Central America; saying the latest group contains approximately 12,000 potential asylum seekers.

“The U.S. government is tracking three separate migrant caravans, one of them estimated to be more than 12,000 people in size, heading north toward the U.S,” reports the Washington Times. “Defense Undersecretary for Policy John Rood told Congress that those caravans are one reason why the presence of active-duty troops is still needed on the U.S.-Mexico border.”

The report comes as Mexican officials rapidly prepare for a second caravan to arrive in Tijuana in the coming weeks; stretching already thin supplies and funds as thousands of migrants stall throughout northern Mexico.

Read the full report at the Washington Times.