Moscow - A prominent Russian rights advocacy group on Tuesday warned of a crackdown on internet users as courts impose harsh jail sentences for posts expressing political views."The Russian authorities have begun to see the internet as a theatre of war, both inside (the country) and outside" where the slightest criticism is "seen as like an armed attack," Agora advocacy group said in a report presented in Moscow.Agora groups together around 50 lawyers specialising in rights cases who have worked on cases including that of Pussy Riot punk group and radical performance artist Pyotr Pavlensky.Increasing pressureIt said that the state policy on the Russian-language internet - known as the Runet - can be summed up with the words "attack," "campaign" and "enemies."The Russian government also focuses on an external threat, with the FSB security service saying it foiled 70 million cyberattacks last year, Agora said, querying the high figure.The advocacy group condemned "strong censorship" of the internet and increasing pressure on ordinary internet users.It said it had recorded seven criminal cases opened against Russians for expressing views online in 2016, five of which reached sentencing, with four ending in a prison sentence.It cites the case of journalist and blogger Alexei Kungurov in the Urals city of Tyumen who was jailed for two years by a military court for online criticisms of Russia's bombing campaign in Syria.He was found guilty of publicly justifying terrorism in December last year over a post on the Live Journal site.Martial lawAn electrical engineer from the central Russian city of Tver, Andrei Bubeyev, was sentenced to two years and three months in a penal colony in May last year.He was found guilty of support for extremist activity and breaches of Russia's territorial integrity after re-posting a pro-Ukrainian article and a picture of a toothpaste tube with the caption: "Squeeze Russia out of yourselves."Agora concluded: "All this allows us to draw a definite conclusion - the Runet has entered a state of martial law."Varying estimates put Russia's number of active internet users at between 66 and 84 million people out of a population of 146 million, Agora said.