President Donald Trump’s promised crackdown on illegal immigration has begun to take shape in San Diego County, as federal agents launched targeted operations to arrest undocumented immigrants and a wave of military troops got to work reinforcing U.

A Border Patrol agent pats down one of four men after the group crossed the border illegally through a gap in two walls separating Mexico from the United States before turning themselves in, Thursday,

After a night of rain that potentially aided firefighting efforts, the Border 2 Fire was 43% contained by Monday morning.

A wildfire in the hills near the U.S.-Mexico border exploded early Friday morning over thousands of acres, prompting evacuation orders throughout the Otay Wilderness Area and triggering school closures as well as likely power shutoffs for tens of thousands of people.

An additional 1,500 troops have arrived at the U.S.-Mexico border after President Donald Trump declared a national emergency in one of his first official acts.

Officials said the fire, which had spread to more than 500 acres by Thursday night, was miles away from threatening any homes or buildings.

Dozens of active duty troops arrived at the U.S.-Mexico border near San Diego on Friday, marking the first batch to deploy following President Donald Trump’s order to bolster border security.

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

CBS 8 spoke with Cal Fire San Diego on how crews battle fires that happen on the Mexico side of the U.S.-Mexico border.

A fire spreading through the wilderness of San Diego County near the U.S.-Mexico border exploded to more than 500 acres within several hours on Thursday night. But the blaze, known as the Border 2 fire, was miles from any structures or homes, and firefighters said they were making progress controlling it.

"It's unprecedented," said Ciudad Juarez municipal official Enrique Licon as workers unloaded long metal bracings from tractor trailers parked in the large empty lot yards from the Rio Grande in order to build a tent city for deportees from the United States.

Rain helped firefighters continue to increase containment on a wildfire that burned thousands of acres and forced evacuation orders and warnings north of the U.S.-Mexico border in San Diego County. The blaze,