The Coalicion de los Derechos Humanos (Human Rights Coalition) of Arizona on Tuesday expressed its concern over what it considers to be an increase in the number of undocumented migrants reported to have disappeared in the state's southern desert.

"Last week, we had the report of nine cases of people reported to be missing in their attempts to cross the border in Arizona, and this week we already have three new cases," coalition spokeswoman Kat Rodriguez told Efe.

She said that the coalition is receiving practically one call per day from families inside or outside the United States who are looking for one of their loved ones.

She also said that they receive all kinds of cases, about people who have not been in touch with their friends or relatives for months or years and people who recently tried to cross the border through the dangerous - and sometimes deadly - desert.

"Last week, we received the case of a family that was looking for a woman with a very particular tattoo of Santa Muerte (Holy Death) who disappeared in 2009. Because of this tattoo, it was possible to identify her body in the Pima County morgue," Rodriguez said.

Currently, the U.S. government does not keep track of the reports of undocumented migrants who have gone missing in the Arizona desert.

Rodriguez said that the Coalicion de los Derechos Humanos over the past year has registered about 60 cases of undocumented migrants who have gone missing in the desert.

"I think that these cases tell us that it's not the time to celebrate. The federal government has reported a decline in the number of deaths of undocumented (migrants), but still during the current year more than 140 people have died," said the activist.

According to data compiled by the U.S. Border Patrol, the deaths of 132 undocumented migrants were reported from Oct. 1, 2010, through July 31 compared to 212 during the same period last year.