President Enrique Pena Nieto and Mexico City Mayor Miguel Angel Mancera, who visited the scene of the blast, said Pemex rescue and security teams were working alongside city authorities to help the injured.
To combat the green-on-blue problem, U.S. and Afghan officials have implemented tighter vetting for Afghan army and police recruits, and now designate one U.S. soldier -- known as a "guardian angel" -- in those U.S Army units working with Afghan security forces whose job is solely to guard against attacks while American forces eat, sleep or exercise, the Associated Press reported.