Mexico's top public safety official, his deputy and seven others died in a helicopter crash in the mountains west of Mexico's capital on Wednesday. There were no survivors.
The helicopter, carrying Public Safety Secretary Ramon Martin Huerta, Federal Preventive Police Chief Tomas Valencia, five other passengers and a crew of two, had taken off from a military parade ground in Mexico City.
It was headed to an event at the maximum-security La Palma prison, 35 miles to the west, when it was lost in dense fog and clouds.
"They all died in the line of duty," President Vicente Fox said in a televised address. His voice cracking with emotion, the president said "They are heroes ... I have lost not just a co-worker, but a close friend, Ramon."
Fox offered no immediate explanation of why the helicopter had crashed in a mountainous, wooded area about 20 miles outside Mexico City.
But Mario Martinez, a pilot who was following in another helicopter, told local media that Huerta's craft had disappeared into a dense bank of clouds and was lost to view.
"They put their lives at risk to lead our nation's fight against criminals and organized crime," Fox said. "They are heroes."
The burned wreckage of the helicopter was reported found by rescue crews after a search of several hours.
Mexican media outlets began speculating within hours of the helicopter's disappearance about the possible involvement of drug trafficking groups.
The flight was on its way to a swearing-in ceremony for prison guards, the culmination of an effort to purge corrupt officials from a prison holding notorious Mexican drug gang leaders.
The prison was cordoned off earlier this year by federal troops after investigators found evidence that reputed drug lords Osiel Cardenas and Benjamin Arellano Felix had joined forces and were operating their networks from behind bars.
In addition to Huerta, the Bell helicopter carried a pilot, co-pilot, Valencia, officials from the Public Safety Department and one official from the country's National Human Rights Commission.
Fox created the Public Safety Department after taking office in 2000, combining federal police forces overseeing prisons, highways and borders _ including the Federal Preventative Police, a force that includes soldiers assigned to police work like crowd and riot control.
A trusted Fox ally, Huerta was appointed to lead the agency in August 2004 after the previous secretary, Alejandro Gertz Manero, resigned to return to private life.
Valencia had been promoted to his police chief post, answering to Huerta, in January after his predecessor was fired for his role in the botched response to an attack by a mob in Mexico City that left two federal agents dead.
Huerta was Fox's campaign director when Fox ran for governor of the central Mexican state of Guanajuato, and served as interior secretary after Fox's election in 1995. When Fox became president, Huerta took over as interim governor of Guanajuato.
Huerta, who has a degree in business administration, worked as a college professor and was an activist in Fox's conservative National Action Party before he launched his government career.
"For me, it is of great concern when any person has been in an accident, or is injured, or killed, but in this case in particular, the friendship that bonds me with Ramon for a long time makes this an extra-personal worry," said Foreign Secretary Luis Ernesto Derbez, who spoke with reporters during an event with a visiting Russian official.