MEXICO CITY — A U.N. rights group is criticizing a proposal by Mexico's leftist Morena party to broaden the list of charges that require suspects be jailed while on trial.

The bill passed last week by Mexico's Senate adds four crimes to those considered so serious that suspects can't be released on bail or personal recognizance.

The list currently includes serious crimes like murder, rape or terrorism, and the measure would broaden add corruption, weapons possession, child sex abuse and fuel theft from government pipelines.

The U.N. Working Group on Arbitrary Detention wrote in a statement Wednesday that pre-trial imprisonment should be imposed only on a case-by-case basis.

At present, Mexican prosecutors can ask judges for pre-trial detention based on the threat a suspect could represent to society, witnesses or victims.