Four people were arrested on Tuesday for allegedly trying to disable U.S. Border Patrol vehicles during an immigration enforcement operation in Van Nuys. 

In a , USBP Chief Patrol Agent Gregory Bovino alleged that the four people had "attempted to impede & obstruct our efforts, using improvised devices aimed at disabling our vehicles."

Two images showed the devices that the suspects allegedly used. They appear to be rubber or metal strips with large nails attached. One of the photos showed the item lodged in a car's tire. 

Bovino said that four people were arrested in connection with the incident, each of whom now faces felony charges.

The arrests came during an immigration enforcement operation outside of a Home Depot on Balboa Place in Van Nuys on Tuesday. A group of federal agents could be seen outside of the hardware store in video posted on social media, though it's unclear how many people, if any, were detained. 

Other video captured by onlookers' cell phones shows agents tackling one man to the ground while several others are detained. 

In a statement shared with CBS News Los Angeles, a spokesperson for the Department of Homeland Security confirmed Tuesday's operation and said that one of the four people arrested for allegedly obstructing law enforcement was also subsequently arrested for assaulting a Border Patrol agent during their initial detainment. 

Later Tuesday, activists gathered for a news conference to argue against what they're calling federal intimidation tactics targeting members of the day labor community. 

"They are not criminals, and the day laborers that they are defending are not criminals. They are essential members of our society," said Maegan Ortiz, the executive director of the Instituto de Educación Popular del Sur de California. "What we are experiencing here today is just a fraction of what families across Los Angeles have been experiencing."

Ortiz says that one of the people detained was Jenaro Ernesto Ayala, an outreach coordinator with IDEPSCA and U.S. citizen. She said he was there to help day laborers at the site. 

"Ernesto was standing up for the rights of workers," Ortiz said in a statement. "His detention is a blatant attempt to silence those who defend our communities, and we won't let it stand."

Her group of activists say that theyhave unable to get in touch with him, so far, and that attorneys have been denied access to meet at the Metropolitan Detention Center in downtown Los Angeles, where he's being held.