A Stockholm-based Kurdish group’s video depiction of Turkish President Recep Tayyip Erdogan swinging by his legs from a rope brought a furious response from Ankara on January 12.

Turkey summoned Sweden's ambassador to lodge an angry protest. Turkish officials raised concerns about what they saw as a soft Swedish government response to the video and tweet from the Rojava Committee of Sweden, which drew a comparison between Erdogan and Benito Mussolini. The Italian Fascist dictator was hung upside down after he was executed in the closing days of World War II.

"History shows how dictators end up," the Rojava Committee of Sweden wrote above a video showing pictures of Mussolini's 1945 execution and then a dummy painted to look like Erdogan swinging on a rope.

"It is time for Erdogan to resign. Take this chance and quit so that you don't end up hanging upside down on [Istanbul's] Taksim Square."

Erdogan, in power for nearly two decades, plans to stand for re-election in polls that are to be held by June at the latest.

Both Sweden and Finland still need assent from Ankara to enable them to join the Nato defence bloc. Turkey has set conditions on providing its backing. One demand is that the two Nordic countries clamp down on Kurdish groups that Ankara views as "terrorists". Turkey often expresses its concern about the activities of some member of the Kurdish diaspora, which is particularly sizeable in Sweden. Erdogan’s officials frequently demand that Sweden extradite Kurdish suspects and prosecute groups such as the Rojava Committee. But Stockholm responds that such matters can only be decided by Sweden’s independent courts.

Erdogan's chief spokesman Fahrettin Altun tweeted that Turkey condemned the Kurdish group's tweet “in the strongest possible terms”.

He added: “We urge the Swedish authorities to take necessary steps against terrorist groups without further delay.”

His tweet was a response to a statement posted on social media by Sweden's Foreign Minister Tobias Billstrom. While condemning the Erdogan video, he wrote that Stockholm supports "an open debate about politics" but "distances itself from threats and hatred against political representatives".

"Portraying a popularly elected president as being executed outside city hall is abhorrent," the Swedish top diplomat also wrote.

The Turkish foreign ministry, however, said Stockholm was going back on past pledges. It demanded that "the perpetrators of this action are found".

Turkey has fought a decades-long insurgency against the outlawed Kurdistan Workers' Party (PKK).