The Kremlin called the owner of Telegram, Pavel Durovbe more careful as the messaging app was allegedly used to recruit the gunmen who attacked the concert venue outside Moscow.

The Telegram app, which is based in Dubaifounded by Durov, who left Russia in 2014 after lost control of his previous company.

Durov, 39, who was born in Russia, lives in Dubai and holds dual citizenship – of the United Arab Emirates and France – according to Telegram.

The representative of the Kremlin, Dmitry Peskovtold Russian news site Life that there are no plans to block the appwhich is a major distributor of news in Russia and around the world, but that Durov should be more careful.

“We would expect more attention from Pavel Durov, because this unique and excellent resource, from a technological point of view, which has been developed, in fact, before our own generation, is increasingly becoming a tool in the hands of terrorists, is being used for terrorist purposes”said Peskov.

RIA news agency reported that the perpetrators had been recruited through a radical network on Telegram belonging to the organization “Islamic State of Khorasan Province” (ISIS-K).

Durov is estimated to be worth $15.5 billionin accordance with Forbes.