"We're very concerned because we see that the United States is returning to policies that appeared to have been left in the past, like having detention centers for children and families," said Gonzalez, who is also the Rapporteur on Migrant Rights.
Gonzalez led a delegation of the Commission this week that visited the U.S. southwest border, where about 66,000 unaccompanied minors-and a similar number of families-from Mexico and Central America have been apprehended since October 2013, registering record numbers .
Some migrant children have been sent to relatives or shelters to await their appearance before an immigration judge.
But the fact that many remain in detention centers is a "setback" and a quick solution "looks complicated," Gonzalez said.
In a statement, the IACHR--an autonomous organ of the OAS--said the detention of migrants is "undesirable" and must be "only used as an exceptional measure" and for a short period. In that regard, it called on the United States to enact legislation to ensure that children and families are not sent to those centers.
The numbers of children caught at the border has been falling since June, but the government has been cautious in declaring the situation resolved. It is currently expanding capacity for detention of migrants.
The Department of Immigration and Customs Enforcement (ICE) plans to open a new facility this year in Dilley, Texas that could accommodate 2,400 beds.
The United States "is returning to policies that existed more than five years ago," Gonzalez said, referring to the center in Hutto, Texas that was forced to cease housing child migrants in response to demands from civil organizations.
The conditions of migrants in the United States is of concern to the Commission, which has already announced a hearing to discuss the issue during the next session later this month.
"Equivalent to prison"
González, accompanied by the Rapporteur on the Rights of Children, Rosa María Ortiz, and other experts, visited the ICE center for children and families in Karnes, Texas, and interviewed former detainees from the center of the Border Patrol in McAllen, Texas since they were denied access to migrants currently detained there.
The U.S. government applies "the same standard as Guantánamo" in the migrant centers, the commissioner said.
Migrants reported lack of privacy and recreation, and restrictions on calling relatives from the centers, according to testimony gathered by the Commission. The Commission considered that the human rights situation has been "exacerbated" by the recent wave of migrant children.
It also noted that the detention is arbitrary and that many migrants lack legal representation, which is a major factor in determining the probability that an asylum case be accepted, Gonzalez said.
For the Commission, the facilities "are equivalent to prisons."
Another complaint is that U.S. authorities do not thoroughly investigate the asylum claims of migrants, who flee drug violence, mainly in Honduras, El Salvador and Guatemala.
"It's a very serious situation of violence in these countries and therefore each case should be analyzed carefully," Gonzalez said.
"This means that people who face risks in their countries are being deported," he added.