Kazakh police on Saturday detained protesters at an unsanctioned rally in Almaty against the devaluation of the national currency, the Interfax-Kazakhstan news agency reported. Around 50 protesters gathered on the main Republic Square in Almaty for a rally against the energy-rich Central Asian country's decision to devalue its currency, the tenge, against the dollar. On Tuesday, the central bank decided to devalue the tenge by about 19 percent against the dollar, prompting widespread panic with some exchange points running out of hard currency. Police put up metal barriers on the square and repelled attempts by some protesters to break through, Interfax-Kazakhstan reported. The protesters then began marching towards the city hall, with their numbers growing to nearly 100. Police guarding the city hall then began making arrests. Most of the activists were detained, put into police vehicles and driven away. Police did not say how many were detained but those arrested were expected to be charged with administrative offences. Police herded the remaining protesters into an area outside a state television building and removed some of the barriers on the square, the agency reported. A representative of the prosecutors' service came out and urged them to disperse, Interfax-Kazakhstan reported. Kazakhstan is Central Asia's largest economy. It has been ruled by President Nursultan Nazarbayev since before its independence from the Soviet Union.