U.S. officials say active duty military troops are arriving in El Paso, Texas, and in San Diego on Thursday evening.

Troops have assisted at the border before and will be limited to support roles unless the administration invokes the Insurrection Act.

The US-Mexico border is effectively closed off to migrants seeking asylum in the United States within hours of President Donald Trump taking office, an extraordinary departure from previous protocols that has left many concerned migrants in limbo.

Thousands of migrants are now in limbo at the U.S.-Mexico border after President Trump shut down the main legal channel for asylum seekers to enter the country. Many had waited months for immigration appointments,

U.S. border agents have been instructed to summarily deport migrants crossing into the country illegally without allowing them to request legal protection.