(Reuters) - Russia detained Grigory Melkonyants, the co-chair of prominent independent vote-monitoring group Golos (Voice), the organisation said on its website on Thursday night.
Law enforcement officers arrived in Melkonyants' apartment early in the morning and after searching his home, took to him the main department of the Russian Investigative Committee for charges, Russian agencies reported.
A court is expected to decide on Friday whether Melkonyants will remain in custody, Golos said referring to his lawyer Mikhail Biryukov.
Melkonyants may face up to six years in prison for working with an international organization, declared "undesirable" by Russian authorities, his lawyer told Russian agencies.
A video published by RIA news agency showed three men in plain clothes standing next to Melkonyants inside his home while one of them ordered Melkonyants to put the time on a paper he was signing - 6.45 a.m. (0345 GMT)
Moscow-based Golos is monitoring election campaigns in dozens of Russian regions ahead of voting scheduled for September.
The group first angered the government by publicising evidence of alleged fraud in a 2011 parliamentary vote that sparked opposition protests, and in the presidential election that returned Vladimir Putin to the Kremlin for a third term in 2012.
The Russian government labelled the group a foreign agent but it continued to work in the country even when Russia intensified a crackdown on dissent after invading Ukraine last year.
The prosecution is likely to be related to the European Network of Election Monitoring Organizations (ENEMO), a Montenegro-based non-governmental organisation, Golos said on its website.
Golos stopped its cooperation with ENEMO after Russian authorities banned activities of the network in 2021, the group said.
Russian law enforcement searched homes of a total of 14 members of Golos in eight Russian regions, RIA reported.
(Reporting by Maria Tsvetkova in New York; Editing by Lincoln Feast)