Speaker 1: Major developments on immigration just days after President Trump declared an emergency at the southern border. A military buildup underway. The first of some 1,500 active-duty troops have arrived. Marines from Camp Pendleton arriving with heavy equipment and Osprey aircraft. And for the first time, military planes are making deportation flights. This C-17 at Fort Bliss, Texas. Migrants in restraint seen boarding a flight to Guatemala. A new image from inside another flight taking off from Tucson, Arizona. Meantime, the administration saying that arrests are ramping up. More than 500 undocumented migrants arrested in multiple cities over the last 24 hours. And tonight, the president's new border czar, Tom Homan, saying this is only the beginning. ABC's chief global affairs correspondent, Martha Raddatz, leads us off tonight.

Speaker 2: Tonight, for the first time, U.S. military aircraft flying undocumented migrants out of the country as President Trump's first flight to Guatemala. President Donald Trump launches his deportation campaign. The White House releasing these pictures, dozens of migrants in chains boarding C-17 aircraft. The flights landing in Guatemala carrying roughly 160 people, men and women. Today, the Trump administration's new borders are Tom Homan telling me it's only the beginning. Is that going to be a constant commitment from the U.S. military? Is it going to be a single day to take deportees out? Yes. This as the military buildup on the border escalates. 1,500 active duty personnel, Army and Marines deploying. Their mission, to support enhanced detection and monitoring efforts and repair and replace physical barriers. ABC's Matt Rivers on the ground in San Diego.

Speaker 3: So right now, these Marines are offloading concertina wire. They're going to bring it right down to the border to reinforce it. It's clearly meant to be a deterrent. Against future migration. And these kinds of supply flights, we might see a lot more of them over the coming months.

Speaker 2: Far from the border, ICE raids and arrests in cities across the country. The days since the president was sworn in, some of them likely long planned, but a clear sign of what's to come. Boston, New York, and Newark, New Jersey. Newark's mayor saying agents raided a small business without a warrant, detaining American citizens in the process.

Speaker 4: People were fingerprinted. Pictures of their IDs and face were taken there. When I got this information, I was appalled.

Speaker 2: The Trump administration releasing numbers showing 538 arrests over the past 24 hours. The White House saying they're initially targeting undocumented immigrants who have committed violent crimes. But Holman acknowledges not everyone swept up in the raids fits that profile. And he has a stark warning to anyone who's in the country illegally. So is this what we will see every single day, ending in what the president has promised is millions and millions being deported?

Speaker 5: Yes. But you can see the number steadily increased, the number of arrests nationwide as we open up the aperture. Right now it's concentrating on public safety threats, national security threats. That's a smaller population.

Speaker 2: So after you do that, then you go after everyone. Everybody who is there illegally.

Speaker 5: If you're in the country illegally, you're on the table. Because it's not okay to violate laws in this country. So if you're in the country illegally, you've got a problem. And that's why I'm hoping those who are in the country illegally, who have not been ordered removed by the federal judge, should leave.

Speaker 2: Holman, it was very clear that those committing violent crimes will be deported first and acknowledges that the show of force, these strong warnings to all undocumented immigrants, are meant to be used against them. They are meant to send a message that they should self-deport, since it would take a very long time and massive amounts of manpower and money to deport an estimated 11 million undocumented immigrants. Whit?

Speaker 1: Martha Raddatz, thank you.