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.

The Trump administration has ended use of the border app called CBP One that allowed nearly 1 million people to legally enter the United States.

Migrants who waited months to cross the U.S. border with Mexico learned their CBP One appointments had been canceled moments after Donald Trump was sworn in as president.

President Donald Trump's promises of mass deportations, which could bring batches of new arrivals fresh off the border bridges into Juárez, has Mexican law enforcement preparing to keep watch for potential trouble.

Hours after Trump’s inauguration, his administration canceled appointments allowing migrants to enter the U.S. to request asylum, leaving many of them stranded on the U.S.-Mexico border.

General Jose Lemus, commander of Ciudad Juarez's military garrison, said the tunnel "must have taken a long time" to build, suggesting "it could have been one or two years".

The CBP One app has been highly popular, functioning as an online lottery system that grants appointments to 1,450 people daily at eight border crossings. These individuals enter the U.S. under immigration "parole," a presidential authority that Joe Biden has exercised more frequently than any other president since its creation in 1952.

Trailers arrived loaded with tent-type equipment to begin constructing a shelter for deported Mexican migrants in Ciudad Juarez on Monday, according to KINT.

Migrants, activists, and religious organizations remained on high alert on Friday at one of the main border crossings between Mexico and the United States in Ciudad Juárez, as Donald Trump prepares to take office again on Jan.

Data shows birthright citizenship hasn't changed much since 2000 as Trump wants to end it for children of illegal immigrants.

In his speech at the U.S. Capitol, Trump outlined a flurry of executive orders he plans to sign during his first day back in office. President Trump signed an executive order Monday aimed at protecting TikTok from a new law banning the app. Legal experts say this order still leaves the company on shaky ground.

Ahead of the inauguration, migrant shelters south of the Rio Grande are far from full, a reflection of the tougher measures imposed on both sides of the border.