UPDATE — 7:00 p.m. ET: Vargas has been released:

A former reporter turned activist who admitted to living in the United States illegally was detained at a Texas airport Tuesday for not having appropriate documentation, TheBlaze has learned.

Jose Antonio Vargas, 30, was detained at McAllen Miller International Airport after traveling to the U.S.-Mexico border to view the situation where thousands of children have crossed into the country.

“He was detained attempting to leave the airport,” a Texas Border Patrol official told TheBlaze. “Because we’re a border community the immigration officials at the airport ask for appropriate documentation. He didn’t have it.”

FILE - In this June 20, 2012, file photo former Washington Post journalist turned immigration reform activist, Jose Antonio Vargas, center, an illegal immigrant himself, speaks in Washington. Immigration authorities said Monday, Oct. 8, 2012, they won't take action against the Pulitzer Prize-winning journalist who was arrested in Minnesota for driving without a valid license. Credit: AP

In this June 20, 2012, file photo, former Washington Post journalist turned immigration reform activist Jose Antonio Vargas, an illegal immigrant himself, speaks in Washington. (AP)

United We Dream, an immigrant activist group, said in a statement that Vargas was trying to board a plane to Los Angeles.

“We stand in solidarity with Jose Antonio and demand for his immediate release, but we must remember that there are thousands of people along the border that live with this same fear every day,” United We Dream managing director Cristina Jimenez said in a statement. “Once again, the Border Patrol has proven to be a rogue agency after arresting Jose Antonio, a low-priority case for detention and deportation. Our undocumented community along the border is trapped within its own country, unable to leave and surrounded by checkpoints. 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.”

Vargas, who arrived in the U.S. from the Philippines when he was 12, publicly admitted his immigration status in 2011. He said he didn’t know he was illegal until he tried to get a driver’s license when he was 16.

Earlier Tuesday, Vargas tweeted a photo of his Philippines passport and a copy of the U.S. Constitution, calling them “the only IDs I have for security.”

Protest outside McAllen Border Patrol Station for detaining Jose Antonio Vargas, a Pulitzer Prize winner who is living illegally in the United States. Vargas He has been detained by Border Patrol in McAllen,Texas after attempting to board a plane to Los Angeles. He traveled to the border in support United We Dream (UWD) and Minority Affairs Council (MAC), a local UWD affiliate, in order to highlight the stories of refugee children who have fled countries in Central America because of increased levels of violence, according to the group's press release.  Photo Obtained by Texas Law Enforcement Official/ TheBlaze

Protesters outside the McAllen Border Patrol station after former journalist Jose Antonio Vargas was detained Tuesday, July 15, 2014. (Photo obtained by TheBlaze)

About 20 protesters gathered outside the McAllen Border Patrol station after Vargas was detained, law enforcement officials told TheBlaze. The McAllen station is where the majority of illegals crossing into the U.S. have been detained after they cross the Rio Grande.