Mexico began returning the bodies of 40 migrants who died in a fire at a detention center in the northern city of Juarez, the government said Friday.

The body of one victim arrived in Colombia, while the remains of seven citizens from El Salvador are being sent overland and are expected to arrive Saturday, Mexico's security ministry said in a statement.

The bodies of 11 Guatemalan migrants are scheduled to be flown out next week, while relatives of six deceased Honduran migrants are in the process of identifying the bodies, it said.

Specialized fingerprint personnel from Venezuela are due to arrive Tuesday to work on identifying victims, the Mexican ministry said.

Thirty-nine people died in the fire last month, including 18 Guatemalans, seven Salvadorans, seven Venezuelans, six Hondurans and one Colombian.

A 40th victim whose nationality is not known died after being taken to hospital.

Five people were severely injured and another nine were transferred to specialized hospitals in Mexico City due to the seriousness of their conditions, the ministry statement said.

Three immigration officials and a private security guard have been detained as part of a homicide investigation into the blaze.

Authorities accused the people in charge of the facility of doing nothing to evacuate the detainees.

Mexican President Andres Manuel Lopez Obrador vowed last month that there would be "no impunity" for those found responsible.