Prominent North American academics have signed a letter supporting Sunday’s Catalan independence referendum. Noam Chomsky was among the signatories criticising the Spanish government’s “political repression” in the region.

In an open letter, tweeted by referendum supporter Julian Assange, Chomsky et al decried the Spanish government’s handling of the issue.

The academics, from the fields of political science, law, economics, human rights, sociology, and history, compared the current government's actions to that of fascist dictator Francisco Franco, who ruled Spain for almost forty years before his death in 1975.

The 70 signatories, from the US, Canada and Mexico, demanded that Spain “immediately ceases the political repression” and enabled "the people of Catalonia to be allowed freely to express their political views.”

“The level of political repression in Catalonia at the moment is of a severe and arbitrary character not experienced since the days of the Franco dictatorship,” the letter reads.

Noam Chomsky and 69 other US, Canadian and Mexican professors sign letter of support for #Cataloniahttps://t.co/76yAh2xTzjpic.twitter.com/AWnxh5BIa2 — Julian Assange 🔹 (@JulianAssange) September 30, 2017

The signatories pointed to the numerous “repressive measures” taken by the Spanish government to disrupt the referendum including the closing of websites “that provide information or commentary on the referendum.”

Other measures outlined include the raiding of “printers and distributors in the greater Barcelona region,” the confiscation of 1.3 million posters and leaflets, and the serving of an injunction against “all pro-independence newspapers and web-based news offices to ban publication of any material related to the referendum.”

Arrest of top-ranking #Catalonia's official sparks protests & clashes with police (VIDEOS) https://t.co/v2FD3OsH3T — RT (@RT_com) September 21, 2017

On September 6, Catalonia’s Parliament passed a bill paving the way for an independence referendum to be held on October 1. The Spanish government, however, insist the proposed referendum is illegal.

Two weeks later the Spanish authorities stormed the ministries and other buildings belonging to Catalonia's regional government. The raid was carried out in search of evidence relating to the planned referendum.

At least 12 Catalan officials have been arrested, including the chief aide to Catalonia's deputy prime minister, Josep Maria Jové. The arrests sparked mass protests in the Catalan capital, Barcelona.

The Spanish government has said that it will physically prevent voters entering polling booths on Sunday and has threatened to arrest the Catalan premier and more than 750 mayors for making public premises available for the referendum.