A “megaleak” of emails believed to be from the primary internet domain of Turkish president Recep Tayipp Erdogan’s ruling party have been made public by Wikileaks, causing the site to be blocked in Turkey.

Wikileaks yesterday published 294,548 emails covering a six-year period to 6 July that it claimed were from the “akparti.org.tr” domain, owned by Erdogan’s Justice and Development Party known as AKP.

The campaign group said the emails were “part one” of the AKP emails and covered 762 mail boxes from “A” through to “I”. The body of emails includes thousands of attached files.

Ahead of the leak, the group tweeted: “#TurkeyCoup: AKP supporters should pay attention. Our pending megaleak of docs both helps & harms AKP. Are you ready to find it all?”

Since the release of the documents, Wikileaks claims access to its website has been blocked by the Turkish government.

A tweet from the group shows a screengrab of wikileaks.org with a blue screen and a message stating an “administration measure” had been taken according to a decision by the “Presidency of Telecommunications and Communication”.

Ahead of the leak, Wikileaks told its followers: “Turks will likely be censored to prevent them reading our pending release of 100k+ docs on politics leading up to the coup.

“We ask that Turks are ready with censorship bypassing systems such as TorBrowser and uTorrent and that everyone else is ready to help them bypass censorship and push our links through the censorship to come.”

The group also claims to have experienced a “sustained attack” to its “infrastructure” following the leak.

In a tweet it said: “We are unsure of the true origin of the attack. The timing suggests a Turkish state power faction or its allies. We will prevail & publish.”

Wikileaks said the emails, obtained a week before the attempted coup from a source, are “mostly used for dealing with the world, as opposed to the most sensitive internal matters”.

The campaign group also said it had moved forward its publication schedule “in response to the government’s post-coup purges”.

The information dump is understood to be a response to the Turkish government’s actions following an attempted coup last week that has seen thousands of officials rounded up in a move widely condemned by Western leaders.

President Erdogan has also expressed the possibility of bringing back the death penalty, abolished in 2004, prompting criticism from heads of the European Union.

Wikileaks first rose to prominence in 2010 after publishing what came to be known as the “Iraq War Logs” – then the largest classified military leak in history.

It included nearly 400,000 reports that documented the war and occupation in Iraq, from 2004 to 2009, as told by soldiers in the US Army.