A group associated with Anonymous has hacked into an Isis supporting website, replacing it with a message to calm down alongside an advert for an online pharmacy.

Isis sites have been moving onto the dark web in an attempt not to be discovered. But a hacking group called Ghost Sec, which is related to Anonymous, took the site down and replaced it with a message telling readers that there was “Too Much ISIS”.

“Enhance your calm,” the full message read. “Too many people are into this ISIS-stuff. Please gaze upon this lovely ad so we can upgrade our infrastructure to give you ISIS content you all so desperately crave.”

The ad — which linked to an online pharmacy where payments can be made in bitcoin — would allow people to click through to by online prescription drugs, including Prozac and Viagra.

Before the site was taken down, it was understood to be one of a number of sites that were sharing and copying Isis propaganda so that it could avoid detection and being shut down. Many such unofficial sites have been created on the dark web, according to security blogger Scot Terban, though a large number of them appear to be unofficial and largely disorganised attempts.

Anti-Isis demonstrations across Europe Show all 10 1 /10 Anti-Isis demonstrations across Europe Anti-Isis demonstrations across Europe Anti-Isis protests in Ankara, Turkey A person holds a flag as police uses tear gas and water cannon in Ankara against demonstrators who protest against attacks launched by Islamic State insurgents targeting the Syrian city of Kobani and lack of action by the government Anti-Isis demonstrations across Europe Anti-Isis protests in Diyarbaki, Turkey Protesters clashing with riot police during a demonstration against Isis in Diyarbakir, southeast of Turkey Anti-Isis demonstrations across Europe Anti-Isis protests in Diyarbaki, Turkey Kurdish protesters in the southeastern city of Diyarbakir Getty Images Anti-Isis demonstrations across Europe Anti-Isis protests in Diyarbaki, Turkey Kurdish protesters clash with Turkish riot policemen in the city of Diyarbakir Getty Images Anti-Isis demonstrations across Europe Anti-Isis protests in Brussels, Belgium Riot police block Kurdish protesters as they gather in front of the entrance of the European Parliament in Brussels AP Anti-Isis demonstrations across Europe Anti-Isis protests in Berlin, Germany Demonstrators, including one holding a sign that reads: "Save the Kurds of Kobane from IS," and many of them members of Berlin's large Kurdish community, march to protest against the ongoing violence by militias of the Isis in Iraq and Syria in Berlin Anti-Isis demonstrations across Europe Anti-Isis protests in Hamburg, Germany Kurds protest against Isis militants advancing through the Syrian border city of Kobani, in Hamburg, Germany Anti-Isis demonstrations across Europe Anti-Isis protests in London, UK Kurdish protesters gather at Heathrow Airport as anti-Isis demonstrations take place across Europe Lisa Campbell Anti-Isis demonstrations across Europe Anti-Isis protests in Paris, France Kurds living in France demonstrate in Paris Anti-Isis demonstrations across Europe Anti-Isis protests in Marseille, France Kurdish people hold flag in Marseille during a protest against the threat of a "Syrian Kurdish population's genocide" by Isis militants and to support the population of the Syrian Kurdish town of Ain al-Arab, known as Kobani

According to some bloggers, Isis supporters have been looking to move their propaganda sites onto the dark web because they are less likely to be discovered and shut down. It is unclear how closely associated the site and the group are, with much of its online activity being done by people who are affiliated with Isis rather than directly associated with the group.

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Isis supporters have been attempting to publish sites on the dark web — a part of the internet made up of pages that are not publicly accessible and often require users to be using tools that provide anonymity.