Update 8:40 p.m. EDT: The U.S. Customs and Border Protection agency issued a statement:

"Mr. Vargas was transported to the McAllen Border Patrol Station where he was processed and provided with a Notice to Appear before an immigration judge. He was released on his own recognizance after consultation with Immigration and Customs Enforcement."

Update 6:15 p.m. EDT: Vargas has been released. He issued the following statement:

"I want to thank everyone who stands by me and the undocumented immigrants of south Texas and across the country. Our daily lives are filled with fear in simple acts such as getting on an airplane to go home to our family. With Congress failing to act on immigration reform, and President Obama weighing his options on executive action, the critical question remains: how do we define American?"

Original story:

The detention on Tuesday of José Antonio Vargas, perhaps the United States’ most famous undocumented immigrant, threatens to escalate already-fiery tensions over U.S. immigration policy at the southern border.

Vargas was detained early Tuesday at the McAllen-Miller International Airport in southern Texas while attempting to board a flight to Los Angeles, where his nonprofit organization, Define American, planned to screen a documentary based on Vargas’ experience as an undocumented immigrant.

Vargas, traveling only with a Philippine passport without a U.S. visa, had traveled to McAllen to visit a shelter for the unaccompanied child migrants who have been coming into the United States by the thousands. He acknowledged earlier this week in a Dallas Morning News interview that he feared being detained in McAllen, as he would have to go through a Customs and Border Protection checkpoint before leaving the area.

Vargas, 33, has lived in the United States since the age of 12, becoming a Pulitzer Prize-winning reporter at the Washington Post before revealing his undocumented status, in 2011. Since then, he has been a high-profile activist for immigration reform and immigrants’ rights. Since “coming out” as undocumented in 2011, he has traveled to 43 U.S. states using his Philippines passport as identification, avoiding deportation in part due to his reputation and low risk to the country.

The detention of such a well-known figure -- the “most privileged undocumented immigrant in the country,” as he himself put it in a Politico Magazine piece last week -- places a spotlight on the Customs and Border Protection agency’s actions on a low-priority case. Immigrant rights’ advocates have long called for a more humane policy toward immigrants who pose no risk to the country, and amnesty for those who arrived in the United States as children.

“It’s immoral that people aren’t free to move around the country they know as home because of a system that seeks to criminalize them,” Cristina Jimenez, managing director for the organization United We Dream, said in a statement Tuesday.

Vargas’s age disqualifies him for the Deferred Action for Childhood Arrivals program, which grants temporary relief from deportation for some immigrants who arrived as children. The United States has gradually refocused its deportation strategy to mainly target those with criminal backgrounds, noted an April report by the Migration Institute. But the report also detected “sharply different enforcement procedures” between the southwest border area and the rest of the country.