Mexico City ( CNN ) -- A 14-year-old accused of ruthless killings on behalf of a Mexican drug cartel boss is a U.S. citizen , a U.S. State Department spokeswoman said Monday . Gini Staab would not provide any further information . `` We have confirmed the boy 's U.S. citizenship but ca n't say anything more about the boy 's situation in the absence of a ( provisional arrest warrant ) signed by at least one of the parents , '' Staab said . Earlier , Staab said that the boy , once his citizenship was confirmed , would be given `` all appropriate consular assistance , just like we would for any U.S. citizen arrested and incarcerated overseas . '' Assistance would include prison visits , information on local attorneys and checks on his welfare , she said . The teen -- reportedly carrying a birth certificate issued in San Diego -- and two of his sisters were detained Thursday at an airport in central Mexico after an anonymous tip alerted authorities he was heading to Tijuana , Mexico , local media reported . A spokeswoman for the Mexican attorney general 's office said authorities detained the 14-year-old Thursday evening on suspicion of working as a drug-cartel hit man , but declined to provide details . But the boy faced a battery of questions from reporters after he was detained , answering questions point-blank as camera flashes lit his face . `` I slit their throats , '' he said , describing what he said was the killing of four people . The teen told reporters after his capture Thursday night that he was an orphan who joined the Pacifico Sur drug cartel when he was 12 . He said Julio `` El Negro '' Padilla , one of the group 's alleged leaders , threatened him . `` I either work or he 'll kill me , '' the 14-year-old said . With his hands shoved into the pockets of his cargo pants , the 14-year-old told reporters that he was paid weekly in dollars and pesos . But in answering questions about whether he knew what he was doing when he allegedly participated in the killings , the teen said he was under the influence of drugs and unaware of his actions . `` No , I did n't know , '' he said . Troops standing beside the teen while the youth was interviewed wore masks to hide their faces -- a common sight in Mexico , where clashes between authorities and cartels have intensified since President Felipe Calderon announced a crackdown shortly after he took office in 2006 . But the teen 's face was clearly visible . Martin Perez , director of Mexico 's Children 's Rights Network , said late Friday that authorities should not have given television cameras and newspaper photographers access to the 14-year-old . `` It was completely inappropriate , the form of presenting him in front of the media , '' he said . `` Everyone has the right to be presumed innocent , '' he said . `` Also , it could put his life at serious risk . We have to remember that this is a fight between criminal organizations . '' CNN 's Claudia Dominguez , Rey Rodriguez , Nick Valencia and Krupskaia Alis contributed to this report .
State Department confirms the man 's citizenship , but offers no further information . ` ` I slit their throat , '' the teen hit man says . ` ` I either die or he 'll kill me , '' he says , describing a Mexican cartel boss .