A Russian lawyer who is defending a prominent Crimean Tatar activist says he was forcibly detained and taken to a Federal Security Service's (FSB) office in Russia-controlled Crimea on January 25.
Nikolai Polozov, who was seen being forced into a car by men in civilian clothes, said he was released two hours later.
He said FSB officers had used psychological pressure in an effort to force him to answer questions related to the case of his client, Ilmi Umerov.
Polozov added that he refused to answer the questions.
Polozov's colleague Mark Feigin said earlier on Twitter that Polozov would risk being barred from representing Umerov if he invoked his right to protect his client's privacy.
Umerov, former deputy chairman of the Crimean Tatars' self-governing body, the Mejlis, was charged with separatism last year after he publicly criticized Moscow's seizure of Crimea from Ukraine in March 2014.
In August, Umerov was forcibly sent to a psychiatric clinic for a month of assessment tests.
The Moscow-based Memorial Human Rights Center has called the case against Umerov "illegal and politically motivated."