A Pulitzer Prize-winning journalist, immigrant advocate and undocumented immigrant was detained while trying to leave a shelter for undocumented children in Texas Tuesday.

Jose Antonio Vargas was detained by U.S. border officials while trying to leave McAllen Airport, according to USA Today.

Vargas, 33, had gone to the area to visit the shelter, attend a vigil and advocate for the Central American children, but he was not aware he would face and problems leaving until he was already there.

A friend texted him last week asking how he intended on getting back from the border, but Vargas dismissed it since he had previous experience crossing the border in California, where he grew up, according to CNN.

Vargas then wrote about being trapped in McAllen for Politico and said, "In the last 24 hours, I realize that, for an undocumented immigrant like me, getting out of a border town in Texas -- by plane or by land -- won't be easy. It might, in fact, be impossible."

He has been detained at the airport and only has his Filipino passport.

Vargas revealed he was an undocumented immigrant from the Philippines, at the age of 12, in a 2011 essay in The New York Times Magazine. Prior to his revelation, he had won a Pulitzer for coverage of the Virginia Tech school shooting.

No official explanation has been given about why he was detained, but someone who met Vargas in McAllen told CNN it was because he doesn't have proper documentation.

"Because I don't have any pieces of paper except my Filipino passport, it's going to be hard for me to actually get out of here at some point when I decide to get out of here in the next couple of days," Vargas told CNN on Sunday.

While approaching the airport security early Tuesday, Vargas tweeted where he was and that he didn't know what was going to happen.