MOSCOW (Reuters) - Russian police have identified 10 key suspects involved in what they call mass civil unrest during a huge opposition protest at the weekend and have already made five arrests, investigators said on Thursday.
Police detained more than 1,000 people in Moscow on Saturday in one of the biggest crackdowns of recent years on an increasingly defiant opposition decrying President Vladimir Putin's tight grip on power.
The Investigative Committee said ahead of another opposition protest planned this Saturday that police planned to arrest more people suspected of involvement in unrest and of using violence against the police at last weekend's protest.
Charges of organising mass civil unrest in Russia carry a penalty of up to 15 years in jail.
A committee statement listed the names of 5 detained individuals, including an aide to hunger-striking Kremlin critic Lyubov Sobol who has warned authorities to allow a free and fair election in Moscow later this year or face weekly street protests.
Sobol is one of 16 opposition-minded candidates the authorities have barred from running in September's election for Moscow's city legislature for failing to collect enough genuine signatures of support, something the opposition says is a lie.
Opposition leader Alexei Navalny, who was jailed for 30 days last week for urging people to take part in Saturday's unauthorised protest, tested negative for poison after falling ill in custody, a Russian state hospital said on Wednesday.
But his personal doctor warned the findings were inconclusive and could be wrong. Navalny was discharged from hospital on Monday and taken back into custody. He has said he believes he may have been poisoned.
(Reporting by Darya Korsunskaya, Maxim Rodionov; Writing by Tom Balmforth; Editing by Mark Heinrich)