Mexican authorities have arrested the secretary for public security of an eastern state on suspicion of co-operating with drug gangs. 

Salvador Rocha Vargas was arrested on Wednesday in the state of Quintana Roo. 

He is one of the most senior public officials to be held over alleged links to Mexico's powerful drug gangs. 

But the governor of Quintana Roo denied that it was being taken over by drug gangs, following the arrest and earlier detentions of other senior officials. 

Mr Rocha Vargas, who has been in office for a year and a half, was detained by the military on Wednesday over his suspected links to organised crime. 

Other senior officials were also arrested - among them the chief of Cancun's tourist police and the state delegate, and his deputy, for the federal attorney general's office. 

But despite the string of arrests the state governor, Feliz Gonzalez Canto, told Mexico's El Universal newspaper that authorities had the resources and capability to fight organised crime in public institutions effectively.