The Committee of National Security said on May 17 that the 62-year-old expert had been arrested in February.

It did not give any details on the case.

The committee's statement comes after weeks of unconfirmed media reports saying that Syroyezhkin had been arrested for alleged espionage.

Syroyezhkin, a native of the southeastern Kazakh city of Almaty, has worked as an expert and analyst at the presidential Institute for Strategic Research since 2006.

He is the author of more than 1,000 analytical and research works on China and Kazakh-Chinese relations, written in Russian, Chinese, and English.

Questions about Syroyezhkin’s whereabouts started circulating in the media after he failed to show up at two conferences in Kazakhstan that he was scheduled to attend.

The head of Kazakhstan’s Bureau for Human Rights, Yevgeny Zhovtis, told RFE/RL at the time that the researcher might have been arrested.