The Mexican government has increased its calculation of the number of people who have disappeared since the start of the country's drug war in 2006 and now lists 22,322 as missing, officials said.

It had said in May that 8,000 people were missing.

Assistant Attorney General, Mariana Benitez, said 12,532 people went missing during the 2006-12 administration of President Felipe Calderon, who declared war on drug traffickers. An additional 9,790 have disappeared since President Enrique Pena Nieto took office on December 1, 2012.

Benitez said that the list of people reported missing during Calderon's government had gone up to 29,707, but that authorities arrived at the figure of 12,532 still missing after finding the rest alive or confirming their deaths.

She said a second list started with the Pena Nieto government showed 23,234 people reported missing between Dec. 1, 2012, and July 31, 2014. She said 13,444 of those had been located, leaving 9,790 still missing.

Authorities have given conflicting figures on missing people since announcing in February 2013 there was an official list showing 26,000 people unaccounted for.

In May, Interior Secretary Miguel Angel Osorio Chong said the number of missing was at 8,000. He didn't mention there were two separate lists and didn't take follow-up questions from reporters during his announcement.

It is unclear how many of the missing were kidnapped or killed by drug gangs, which frequently bury their victims in clandestine graves.

Benitez said disappearances are not only linked to drug violence. She said other causes include "voluntary absence, absence due to domestic problems, kidnapping, migration within the country or internationally, confinement in a correctional facility (and) death."

She didn't take questions during a brief message to the media to announce the new figure.