SAN DIEGO — Migrants waiting to enter the US using former Joe Biden’s CBP One app broke down in tears after their appointments were canceled the moment President Trump took office Monday – just the first of the sweeping border actions the new administration prepared for the first day. 

The app – which hundreds of thousands of migrants have used to enter the country since Biden introduced it two years ago – went dark at noon — the very moment Trump was sworn in. 

Migrants were no longer able to make immigration appointments, and the app showed a message that any outstanding interview dates were canceled.

Footage taken by a Washington Post reporter across the border in Jaurez captured the anguish some migrants faced upon learning their shot at making it into the US had vanished – including one woman whose appointment was scheduled for just an hour after the app’s closure.

The woman sobbed silently and slumped to her knees, while others stared despondent with tears rolling down their cheeks.

During his inaugural address, Trump declared that the border crisis is a national emergency and announced he was sending troops to the border to enforce order.

He also outlined plans to use the Alien Enemies Act – which dates back to 1798, and was used in the Second World War to round up Japanese-Americans and put them in internment camps – to battle violent migrant gangs like Tren de Aragua and MS-13 that have claimed a foothold in the US.

Those gangs – which are made up of migrants from Venezuela and El Salvador — will also be designated terrorist organizations.

Trump was additionally expected to sign an executive order ending birthright citizenship for the children of illegal immigrants born on US soil.

He will terminate Biden administration policies like mass humanitarian parole, which gives special admission to the US for migrants from Haiti, Cuba, Nicaragua and Venezuela.

And Biden’s so-called “catch and release” policies – which allowed the vast majority of migrants stopped at the border to be set free into the US – is expected to be halted as well.

Border wall construction will also resume, and “Remain in Mexico” will become US policy again — forcing asylum seekers to remain outside the US while awaiting their immigration hearings. 

In total, Trump announced plans to ink 11 sweeping border reforms within hours of his inauguration — an effort to undo a historically massive surge of 8 million migrants under Biden. 

Border Patrol agents at near San Deigo told The Post Monday that illegal migrants are still finding a way in and that more needs to be done to stop them.

“They’re still coming in,” one agent said. 

The Post witnessed gaps in the border wall that allowed people to walk right through.

“The cartels are still smuggling them across the border,” the agent added.

Manny Bayon, the National Border Patrol Council President for the San Diego sector, estimated agents are apprehending about 1,000 people trying to cross illegally per day.

“We have to fix open gaps on the border. There are gaps in San Diego where they can walk right into the country.”

There are an estinated 270,000 migrants waiting on the Mexico side of the southern border who had been trying to make it into the country before Trump took office.

Most were hoping to make it to the border in time to utilize the CBP One app, which allowed over 43,000 people per month to schedule meetings with immigration officials at American ports of entry and gain legal entry into the country.

Since Biden introduced it in January 2023, more than 900,000 migrants have used it to enter the country.

Immigration and Customs Enforcement (ICE), meanwhile, was set to begin carrying out mass deportations of illegal immigrants at sanctuary cities across the country after Trump took office again — but the operation was been temporarily halted after details of raids were publicly reported.