The governor of Mexico's northern state of Chihuahua, Javier Corral, has said his government does not have the means to tackle organised crime.
He said he had requested federal resources to help local police fight the drug cartels.
Mr Corral's comments come four days after the murder of a local journalist, Miroslava Breach, in Chihuahua City.
Ms Breach had reported extensively on the links between organised crime and politicians in the state.
She was shot in her car on Thursday outside her house in Chihuahua City, becoming the third journalist killed in Mexico this month.
One of her children, who was in the vehicle, was not hurt.
'For being a loud mouth'
Mr Corral said there had been "significant progress" in the investigation since Sunday.
Police have released a surveillance camera image of one of the men suspected of shooting her. But no arrest warrants have been issued so far.
Mr Corral said that Chihuahua will not be able to combat the powerful criminal organisations operating in the state without federal help.
"The Federal Government is notably absent in the fight against violence in Chihuahua, even though 75% of the murders that happen here are in the remit of the federal authorities," he told La Jornada newspaper.
Ms Breach worked for La Jornada and a regional newspaper, Norte de Juarez.
The gunmen left a note at the crime scene that read: "For being a loud-mouth."
On Friday and Saturday, dozens of her colleagues and other demonstrators took part in protests calling for justice and demanding a thorough investigation.
The Committee to Protect Journalists says 38 journalists have been killed in Mexico since 1992.