At least nine people had been detained in Tajikistan in connection with last week’s deadly attack at a Moscow region concert hall, Reuters and Russian state media reported Friday, citing anonymous Tajik security sources.“Nine residents of Vahdat district [in western Tajikistan] were detained over links to the people who committed the terrorist attack on Crocus City Hall on March 22,” the RIA Novosti news agencyquoted its source as saying.The source added that the Tajik intelligence services were working together with their Russian counterparts in an investigation.According to Reuters’ source, the nine people had been detained on Monday, two days after the attack, and brought to the Tajik capital of Dushanbe.Both news outlets reported that those detained in Tajikistan are believed to have links to the Islamic State’s affiliate ISIS-K.It was unclear whether the nine people faced criminal charges or if Moscow was seeking their extradition.In Russia, authorities said 11 people including four gunmen have been arrested on terrorism charges.

Eight of them have been remanded into custody and a ninth “financier” is expected to appear in court on Friday.ISIS-K claimed responsibility for the Crocus City Hall massacre, in which at least 144 people were killed and 382 others were wounded.Moscow has blamed radical Islamists, Ukraine and its Western allies for the deadliest attack in Russia since the 2004 Beslan school siege.