Tajik security authorities detained nine people last week in connection with the March 22 deadly attack on a concert hall the Russian city of Krasnogrosk.

All nine were reportedly detained by the State Committee for National Security (SCNS) in Vahdat Township on March 25, and brought to Dushanbe. They are allegedly also suspected of having connections with the Islamic State (IS) terrorist group, which has claimed responsibility for the Crocus City Hall terrorist attack.

Meanwhile, citing its source within the law enforcement authorities, Radio Liberty’s Tajik Service reported on March 26 that six members of an organized group were detained in Vahdat on suspicion of plotting a terrorist attack.  The source reportedly didn't provide further details.

A source within the SCNS told Asia-Plus that 15 people were arrested in Dushanbe and Vahdat on suspicion of plotting terrorist attacks in the capital and Vahdat during the Navrouz celebrations.

It is not known whether the 15 detainees are related to those suspected of attacking a concert hall in Krasnogorsk on March 22 and killing at least 143 people.   

Russia's Investigative Committee said on March 28 that it had detained another suspect in relation with the attack on the Crocus City Hall venue.  The committee didn’t provide details of the suspect’s identity or alleged actions, but said he was detained in suspicion of being involved in financing the attack.

Recall, Russian authorities have previously said that 11 suspects had been arrested, including four men who allegedly carried out the attack.  Those four -- identified as Tajik citizens Muhammadsobir Fayzov, Saidakram Rajabalizoda, Dalerjon Mirzoyev, and Faridoun Shamsiddin appeared in a Moscow court on March 24 on terrorism charges.

Another Tajik, Lutfulloi Nazrimad, 23, appeared on March 29 in the Basmanny Court of Moscow for a closed-door hearing.  According to Kommersant, Nazrimad was detained on March 23.  He pleaded guilty to disturbing public order and was sentenced by the Preobrazhensky District Court to administrative arrest for 15 days.