The protest surged at the Immigration and Customs Enforcement facility after Guadalupe Garcia de Rayos was taken into custody during a routine check-in with the agency, according to media reports.
The activists said it was an attempt by President Donald Trump’s administration to deport immigrants living in the country illegally who had previously not been a priority for deportation under the Obama administration.
Fearing the 36-year-old woman’s return to Mexico, dozens of immigration activists blocked the gates surrounding the office near central Phoenix in what the Arizona Republic said was an effort to stop several vans and a bus from leaving.
The protesters said Garcia de Rayos was in one of the vehicles, which were used to transport people in ICE custody to detention centers, or to Arizona’s border with Mexico for deportation. A Republic photo identified a woman looking through one of the vehicle windows covered by security screening as Garcia de Rayos.
Police, meanwhile, took positions around the building and confronted some of the demonstrators, many who chanted “Justice!”
Police posted on Twitter that they arrested about seven protesters, but added that the demonstration was mainly peaceful.
“Besides the few people engaged in criminal acts, most people out here are peaceful and exercising their rights properly,” police said. “Everyone remains safe so far. Hoping for continued cooperation and no more criminal conduct.”
By 1 a.m. Thursday, less than two dozen protesters stood in the dark outside the building talking quietly, with just a handful of police looking on.
The protesters said they initially succeeded in stopping the vehicles from leaving, but said they later left the grounds by another exit. They didn’t know if Garcia de Rayos had still been aboard.
Her arrest came just days after the Trump administration broadened regulations under which some people will be deported.
“We’re living in a new era now, an era of war on immigrants,” Rayos’ lawyer, Ray A. Ybarra Maldonado, told the New York Times after leaving the immigration building.
Puente Arizona, an immigrant advocacy group, said García de Rayos came to the U.S. as a 14-year-old and now has two children. She was arrested on Wednesday while reporting to ICE, an annual requirement.
Her status with the agency wasn’t immediately clear late Wednesday. The Republic carried a statement from ICE officials, which said only that she was detained because of her prior conviction.
Phoenix station KTAR reported that she was arrested in 2008 during a workplace raid and was later convicted of identity theft for possessing false papers.
Despite her conviction, she was allowed to live in Arizona and checked in with ICE officials every six months.
AP writer Astrid Galvan contributed to this report.