MEXICO CITY - The former mayor of the southwestern city of Iguala has been charged with last year's kidnapping of 43 students who are feared to have been killed, a top security official said on Tuesday.

Tomas Zeron, director of criminal investigations at the federal Attorney General's office, said that prosecutors had obtained an arrest warrant for former mayor Jose Luis Abarca and 44 others on charges of kidnapping the 43 students.

President Enrique Pena Nieto is facing his deepest crisis over the government's handling of the investigation. Anger over the case spurred sometimes violent demonstrations around the country late last year.

Zeron did not specify when the warrant was obtained, but it appeared to be the first charges filed against Abarca that are directly related to the students' disappearance even though authorities have said the mayor and his wife were the masterminds of the kidnappings since October.

Zeron spoke to reporters after meeting with family members of the missing students.

The students were allegedly abducted by police working with a local drug gang in the southwestern city of Iguala on the night of Sept. 26. On Monday, the federal courts authority said a judge had ruled Abarca's wife will stand trial for links to organized crime.

Abarca and his wife, Maria de los Angeles Pineda were captured by federal police in Mexico City in November.

Abarca was already facing charges of links to organized crime as well as kidnapping and murder charges related to other cases besides the students.