MEXICO CITY (Reuters) - A report found that staff at Mexico’s National Migration Institute (INM) abused and even tortured migrants held in detention centers across the country, a finding the organization disputed on Thursday.

INM commissioned the report, which was conducted by human rights works and others from outside the government agency. It was not clear why the agency commissioned the report but Mexico’s migration officers have long been accused of corruption, shaking down migrants and even working with organized criminals involved in human smuggling rings.

INM said it has taken steps to safeguard against the problems highlighted by the report but disputed the report’s most serious findings.

“The INM has not received, up until this point, any complaint or recommendation of any grave violation of the human rights, such as torture or solitary confinement, of detained foreigners,” it said. “The INM treats all migrants in detention centers with the absolute respect of their human rights.”

Mexico’s Interior Ministry, which oversees the INM, directed all questions to the INM.

The migrants, most of whom come from Guatemala, Honduras and El Salvador, complained of regular physical and verbal abuse, including death threats, the report said. Migrants were “systematically” kept in “punishment cells” or in solitary confinement, it added.

The report also found that extortion of detained migrants was “generalized,” with several examples of sexual abuse of women.

The number of Central American migrants bound for the United States has fallen sharply since U.S. President Donald Trump took office, vowing to crack down on illegal immigration.

However, history shows that the numbers could rise if Trump fails to realize his tough policies.