Police in the Mexican town of Iguala have found mass graves near the same place where 43 students went missing last month.

The Mexican newspaper El Proceso says authorities have begun digging up bodies and are trying to determine their identities.

The Wall Street Journal quotes Guerrero State Prosecutor Inaky Blanco as saying the graves were linked to the disappearance of the students but that it would "irresponsible" to jump to conclusions and say the bodies are those of the students.

The Journal adds:

"The students disappeared last weekend after police in the city of Iguala killed six people when they fired on the students, who had hijacked local buses. Among the dead were three students and a high-school soccer player. ..."Thirty people, including 22 municipal police officers, had so far been detained in the case, officials said. Meanwhile, Iguala's mayor and police chief, who are wanted for questioning, appear to have gone into hiding, officials said."The killings and disappearances in Iguala underscore Mexico's continuing inability to clean up corrupt local police forces which officials acknowledge in many areas are in league with the nation's powerful organized crime groups."

The AP reports that the The Aytozinapa Normal school, where the missing students attended, is "known for militant and radical protests that often involve hijacking buses and delivery trucks."

The AFP reports that Governor Angel Aguirre appealed for calm.

"I call on all [Guerrero state residents] to maintain harmony, non-confrontation, and avoid violence," he said.

Copyright 2016 NPR. To see more, visit http://www.npr.org/.