MOSCOW (AP) — The chief of the Russian communications watchdog acknowledged Wednesday that millions of unrelated IP addresses have been frozen in a so-far futile attempt to block a popular messaging app.

Telegram, the messaging app that was ordered to be blocked last week, was still available to users in Russia despite authorities' frantic attempts to hit it by blocking other services.

The row erupted after Telegram, which was developed by Russian entrepreneur Pavel Durov, refused to hand its encryption keys to the intelligence agencies. The Russian government insists it needs them to pre-empt extremist attacks but Telegram dismissed the request as a breach of privacy.

Alexander Zharov, chief of the Federal Communications Agency, said in an interview with the Izvestia daily published Wednesday that Russia is blocking 18 networks that are used by Amazon and Google and which host sites that they believe Telegram is using to circumvent the ban.

Countless Russian businesses — from online language schools to car dealerships — reported that their web services were down because of the communication watchdog's moves to bloc networks.

Internet experts estimate that Russian authorities have blocked about 16 million IP addresses since Monday, affecting millions of Russian users and businesses.

In the interview, Zharov admitted that the authorities have been helplessly trying to block Telegram and had to shut down entire networks, some of which have over half a million IP addresses that are used by unrelated, "law-abiding companies," he said.

Russia's leading daily Vedomosti in Wednesday's editorial likened the communications watchdog's battle against Telegram, affecting millions of users of other web-services, to warfare.

"The large-scale indiscriminate blocking of foreign IP addresses in Russia in order to close the access to the messaging app Telegram is unprecedented and bears resemblance to carpet bombings," the editorial said.

Zharov also indicated that Facebook could be the next target for the government if it refuses to comply with Russian law.

Authorities previously insisted that Facebook store its Russian users' data in Russia but has not gone through with its threats to block Facebook if it refuses to comply.

Zharov said authorities will check before the end of the year if the company is complying with its demands and warned that if it does not, "then, obviously, the issue of blocking will arise."

Elsewhere in Moscow, a court on Wednesday sentenced a member of the punk collective Pussy Riot, who spent nearly two years in prison for a protest in Russia's main cathedral, to 100 hours of community work for a protest against the Telegram blocking. Maria Alekhina and a dozen activists were throwing paper planes outside the communications watchdog's office on Monday.