Alexander Bortnikov, the head of Russia’s Federal Security Service (FSB), announced on Wednesday that terrorists groups are using secret chats on the instant messenger Telegram to coordinate their efforts.

While speaking at a security conference for intelligence agencies in the Commonwealth of Independent States, Bortnikov said FSB agents have obtained evidence that terrorists communicate through closed groups on Telegram, according to the news agency RIA Novosti.

“We have information about specific terrorists and criminal connections inside Russia and Central Asian countries using [these] communications, and we’ve discovered [some of] their plans and probable locations,” Bortnikov said.

Earlier on Wednesday, lawmakers in the State Duma introduced draft legislation that would ban anonymous instant messenger accounts and place other new restrictions on apps like Telegram and WhatsApp. The law would also empower the federal censor to restrict messengers from allowing mass mailings that contain information outlawed in Russia.

Telegram’s “secret chats” use end-to-end, client-client encryption, and all content shared in secret chats is device-specific and kept separate from the Telegram cloud.

Testifying before the U.S. Congress in March 2016, a chief lawyer for the tech company Apple called Telegram “one of the most pernicious apps that we see in the terrorist space.”

In the past few years, public channels on Telegram have become a potent political and social platform in Russia. In a recent trend, anonymous users have launched channels where they analyze politics and share rumors about current affairs.

Russian Intelligence Chief Says Terrorists Use Telegram's ‘Secret Chats’