Mexico's former deputy defense minister and a top army general are being questioned for suspected links to organized crime.
Mexican soldiers on Tuesday detained retired general Tomas Angeles Dauahare and general Roberto Dawe Gonzalez and turned them over to the country's organized crime unit, military and government officials said.
This is the highest-level scandal to hit the military in the five-year-old drug war initiated by President Felipe Calderon.
More than 50,000 people have died in drug-related violence since then.
Angeles was assistant defence minister from 2006-2008 and helped lead the government's crackdown on drug cartels after soldiers were deployed to the streets in late 2006.
Gonzalez, still an active duty general, led an elite army unit in the western state of Colima and local media said he previously held posts in the violent states of Sinaloa and Chihuahua.
An official at the attorney general's office, said the generals would be held for several days to give testimony and then could be called in front of a judge.
Prosecutors said the generals had not been charged with any wrongdoing, but were "giving their declarations in connection with the investigation carried out by the organised crime unit".
If the generals were convicted of drug trafficking, it would mark the most serious case of military corruption during Calderon'sadministration.
Worsening drug-related attacks in major cities are eroding support for Calderon's conservative National Action Party, or PAN, ahead of a July 1 presidential vote.
Over the weekend, police found 50 headless bodies on a highway in northern Mexico, the latest in a recent series of brutal massacres where mutilated corpses have been hung from bridges or shoved in iceboxes.