Mexico’s Migration Institute (INM) said Wednesday it will suspend operations at 33 immigration detention centers while the country’s rights watchdog completes a review of the sites following a fire that killed 40 people who were in government custody.

The facilities, located nationwide, can house up to 1,300 people at a time for stays of up to seven days, the migration institute said in a statement.

They will remain closed until the National Human Rights Commission (CNDH) can inspect the sites and issue a final report.

The institute added that it will continue to operate other detention centers, without detailing how many are currently open. Until last year, the INM operated a total of 57 detention centers with a capacity for more than 6,800 people.

The INM said last month that it would work with the rights commission to assess conditions at migration centers. Immigrant advocates had demanded close scrutiny after a fire in a detention center in the northern border city of Ciudad Juárez in March killed 40 people and injured others.

The director of the institute, Francisco Garduño, has been accused of illegal exercise of public office for the fact. He remains in his post and has said he will not comment while the case is ongoing.