McALLEN, Texas (AP)  Prominent immigration activist and Pulitzer Prize-winning journalist Jose Antonio Vargas, who has lived and worked in the U.S. illegally for years, was released by U.S. Border Patrol agents on Tuesday after being detained at a South Texas airport.



In a statement late Tuesday, the Border Patrol said Vargas was arrested at the airport in McAllen after telling an agent he was in the country illegally. Vargas was released on his own recognizance with a notice to appear before an immigration judge.



"Mr. Vargas has not previously been arrested by (Immigration and Customs Enforcement) nor has the agency ever issued a detainer on him or encountered him," the statement said. "ICE is focused on smart, effective immigration enforcement that prioritizes the agency's resources to promote border security and to identify and remove criminal individuals who pose a threat to public safety and national security."



A spokeswoman for Define American, Vargas' advocacy group, confirmed his release Tuesday afternoon, but declined to offer more information about his release or whereabouts.



During the current surge in immigration in South Texas, it has been common for the Border Patrol to release people on their own recognizances, with notices to appear in court later. With such notices, people can generally travel throughout the U.S. without being detained again.



Vargas had been visiting McAllen for several days as part of a vigil to highlight the plight of unaccompanied immigrant children coming into the U.S. illegally who have overwhelmed Border Patrol facilities.



But at McAllen/Miller International Airport, Vargas knew he could have problems. Border Patrol agents stand alongside Transportation Security Administration personnel to check documentation  even for domestic flights. Vargas does not have any government-issued U.S. identification and was carrying only a passport issued by his native Philippines and a palm-size copy of the U.S. Constitution.



On Tuesday morning, Vargas tweeted: "About to go thru security at McAllen Airport. I don't know what's going to happen."



The security checks at the airport  and elsewhere in the Rio Grande Valley  are familiar to people living along the Texas-Mexico border.



Along highways out of the area, drivers are stopped at Border Patrol checkpoints about an hour's drive north of the border. It's not uncommon for children who entered the country illegally with their parents and are growing up in the Rio Grande Valley to stay at home when classmates on field trips take those roadways to visit San Antonio.



In recent years, some U.S. citizens who object to being asked about their citizenship at the interior checkpoints have taken to refusing to answer agents' questions or producing identification. Some have recorded those encounters and later uploaded the video to the Internet.



But Ryan Eller, campaign director for Define American, the advocacy group founded by Vargas, said that Vargas was unaware he would have to pass through such immigration checks in order to leave the city.



"We had been to border towns before like San Diego and other places, but we didn't recognize until (we got) here the situation," Eller said while standing across the street from the Border Patrol station where Vargas was being held.



Eller confirmed the only identification Vargas carried was his Philippines passport. He said Vargas was en route to Los Angeles and that he had consulted with attorneys before going to the airport. Eller said a "travel partner" was at the airport with Vargas, but that they were immediately separated in security.



Vargas' attorney referred questions to Define American.



Vargas had flown to McAllen last Thursday to take part in the vigil. In an essay he wrote for Politico on Friday, Vargas said he has travelled in the U.S. for years without a problem but didn't realize those driving or flying out of the Rio Grande Valley in South Texas are subject to immigration checks.



Vargas went public about his immigration status in a 2011 piece for the New York Times Magazine. He was part of the Washington Post team that won the Pulitzer Prize in 2008 for coverage of the Virginia Tech massacre. He later directed a documentary called "Documented" and founded his activist group.