Witnesses said one man was in the courthouse parking lot with his son just before 9:30 a.m. when federal agents surrounded and detained him. Two more men were later taken into custody after leaving the courthouse.
The arrests were caught on camera.
Immigrant rights advocates say similar enforcement operations are on the rise.
"This is a state courthouse, as you know, immigration proceedings do not happen at state courthouses but we're seeing this increasing and really alarming trend of arrests happening either right outside the steps like we've seen today or nearby the courthouse," said Hector Pereyra of the Inland Coalition for Immigrant Justice.
The Inland Coalition for Immigrant Justice said Thursday's arrests bring the total number of people taken into custody at or near the courthouse to 33 since last year.
"It's kind of arrest now and ask questions later, a practice that they are engaging in right now which is incredibly unlawful," Pereyra said.
Advocates also warned enforcement actions near courthouses can create fear and raise safety concerns as families, attorneys and members of the public regularly pass through the area.
"The arrests that are happening here could lead to that escalation of violence because federal agents are being trained to escalate not deescalate," Pereyra said. "It puts everyone at the courthouse in harm's way."
After this story aired and was published Thursday, a spokesperson for the Department of Homeland Security sent the following statement to ABC7:
"On April 9, ICE and CBP conducted targeted immigration enforcement operations in Rancho Cucamonga, California, resulting in the arrest of three criminal illegal aliens.
"Godofredo Chiquete Lopez is a criminal illegal alien from Mexico. After his arrest for assault with a deadly weapon and hit and run, ICE requested San Bernardino sanctuary politicians not release this violent criminal from jail, but the sanctuary politicians REFUSED to cooperate with ICE and RELEASED this criminal back into our communities. He entered the country on December 8, 2007, on a B2 tourist visa with authorization to remain no later than June 7, 2008-almost 16 years ago. This criminal will remain in ICE custody pending removal proceedings.
"Alexander Pacheco Sabogal is a criminal illegal alien from Colombia. After his arrest for battery, ICE requested sanctuary politicians not release this violent criminal from jail, but sanctuary politicians REFUSED to cooperate with ICE and RELEASED this criminal back into our communities. He illegally entered the country in 2022 near San Luiz, Arizona, and was RELEASED into the country by the Biden administration. An immigration judge ordered him removed in 2023 after he failed to show up for his hearing. This criminal will remain in ICE custody pending removal.
"Cesar Andres Mendez Garzon is an illegal alien from Colombia who was released into the country by the Biden administration. He illegally entered the country in 2023 near Lukeville, Arizona. An immigration judge ordered him removed in 2025 after he failed to show up for his hearing. This illegal alien will remain in ICE custody pending removal.
"We need state and local law enforcement engagement and information, so we don't have to have such a presence on the streets. If we work together, we can make America safe again. Elected officials who refuse to cooperate with DHS law enforcement are wasting law enforcement time, energy, and resources, while putting their own constituents in danger. 7 of the top 10 safest cities in the United States cooperate with ICE. Sanctuary policies have consequences, and unfortunately, they are the murder, rape, assault, robbery, or drug overdose of American citizens."