Mexico's high court has rejected the latest effort by federal prosecutors to try former President Luis Echeverria in connection with a 1968 massacre of student protesters.

In a 3-2 vote Wednesday, the Supreme Court ruled not to hear an appeal of a lower court ruling which threw out criminal charges against former President Echeverria.

Federal prosecutors had sought charges of genocide against him in connection with the 1968 incident in which soldiers and police fired on student protesters, killing as many as 30.

Echeverria was Mexico's interior minister at the time.

He was president from 1970 until 1976. Authorities have also alleged he was responsible for the June 1971 murder of dozens of young protesters who were beaten to death during a march through Mexico City.

Judges last year rejected those charges for insufficient evidence.

Some information for this report was provided by AP and Reuters.