Turkey on Thursday summoned Sweden's ambassador to lodge an angry protest over a video posted by a Kurdish group in Stockholm that depicted President Recep Tayyip Erdogan swinging by his legs from a rope.
The diplomatic spat threatened to set back Sweden's efforts to break down NATO member Turkey's resistance to its bid to join the Western defence alliance in response to Russia's invasion of Ukraine.
The ambassador was summoned a day after the Kurdish Rojava Committee of Sweden compared Erdogan to Italy's late dictator Benito Mussolini in a tweet.
The Fascist ruler was hung upside down after his execution in the closing days of World War II.
"History shows how dictators end up," the group 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."
The tweet came as Turkey piles pressure on Sweden and fellow NATO hopeful Finland to clamp down on Kurdish groups it views as "terrorists".
Sweden has a larger Kurdish diaspora and a bigger dispute with Turkey.
Ankara has dug in its heels during protracted negotiations that hinge on the extent to which Sweden is ready to meet Turkey's demand to extradite Kurdish suspects and prosecute groups such as the Rojava Committee.
It lashed out furiously Thursday at both the Rojava Committee and what it deemed as Stockholm's soft response to the tweet.
- 'Open debate' -
Erdogan's chief spokesman said Turkey condemned the Kurdish group "in the strongest possible terms".
"We urge the Swedish authorities to take necessary steps against terrorist groups without further delay," spokesman Fahrettin Altun tweeted.
His message came in direct response to a tweeted statement from Sweden's Foreign Minister Tobias Billstrom condemning the video.
Stockholm supports "an open debate about politics" but "distances itself from threats and hatred against political representatives", Billstrom wrote.
"Portraying a popularly elected president as being executed outside city hall is abhorrent," the Swedish diplomat wrote.
Billstrom's message did little to appease Ankara.
The Turkish foreign ministry summoned the Swedish ambassador for a dressing down that included accusations of Stockholm going back on its past promises to Ankara.
"Our expectation is that the perpetrators of this action are found," a diplomatic source said.
The Anadolu state news agency then announced that Turkey's parliament speaker had revoked an invitation for his Swedish counterpart to visit Ankara next Tuesday.
The angry exchange over a tweet came less than a month after Billstrom paid a cordial visit to Turkey in an effort to get the NATO membership bid over the line.
The Swedish government has since signalled that it has reached the limit of what it can do to meet Erdogan's demands before Turkey's next election -- now expected some time before June.
Turkey has been battling a decades-long insurgency against the outlawed Kurdistan Workers' Party (PKK) that has claimed tens of thousands of lives.
But it has also used its fight against the PKK to justify prosecuting Kurdish politicians and support groups.
Turkey's top court is now weighing whether to ban the country's main Kurdish-backed party before the polls.