"There is nothing we could add to the Russian foreign ministry's exhaustive statement on the matter," Boris Labusov, head of the service's press office, told RIA Novosti.
Qatar's security agencies are accusing Russian nationals of an assassination attempt on Chechen separatist leader Zelimkhan Yandarbiyev.
Russian acting Foreign Minister Igor Ivanov issued a statement, saying Russia was not involved in the assassination attempt.
Mr Ivanov issued the statement yesterday night and demanded that the illegally imprisoned Russian residents be released immediately.
In the early hours of February 19, the Qatar security agencies arrested three Russian nationals who were on a business trip to the country and were staying at the Russian embassy in Doha. The arrest was made by brute force, reads the foreign ministry's statement.
"The aforementioned Russian citizens, one of whom holds a diplomatic passport, are Russian security officers. They were attached to the embassy and their sojourn in Qatar was legal. They were gathering and analysing information as part of an anti-terrorist effort, and they did not violate the host country's law. Their actions fall in line with the international anti-terrorism coalition's efforts to trace financial sources and channels, organisational arrangements and other means of support for terrorist organisations," reads the statement.
Mr Ivanov said one of the arrestees had been released after talks with the authorities and was staying at the Russian embassy. The foreign ministry is working to have the rest of the arrestees freed. The Qatar authorities are responsible for the life and health of the other two Russians in custody, noted Mr Ivanov.
A Russian embassy worker told RIA Novosti on the telephone that the released man was feeling well.
