Turkish President Recep Tayyip Erdogan said on Sunday that Ankara's relations with Stockholm could head to new lows if the Scandinavian country continues to neglect the presence of the Kurdistan Workers' Party (PKK) on its territory, a party that is labeled  terrorist by Ankara. 

Earlier this month, Kurdish PKK supporters held a rally in Stockholm with a figure of Erdogan hanging by his feet. 

Following a video posted on social media of the event, Turkey summoned the Swedish Ambassador on Thursday to convey a message of anger regarding the incident.

"Our relations with Sweden may become much more strained if they do not take a stand against this situation," Erdogan said at a youth meeting in the city of Mugla on Sunday, adding that the demonstrations were held at multiple locations in Finland, Germany, France, and the UK.

 "Unfortunately, these terrorist organizations continue to appear in all of [these countries]. Of course, as Turkey, we will determine our attitude towards them accordingly," Erdogan said. 

Erdogan has refused to allow both Sweden and Finland to join NATO without primarily taking into consideration their support for the KPP and the YPG.

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On June 28 of last year, Finland's President Sauli Niinisto confirmed that Turkey has agreed to support Finland and Sweden's joint membership of NATO, on the first day of the alliance's summit in the Spanish capital Madrid. The Finnish head of state said the breakthrough came after the three countries signed a joint memorandum "to extend their full support against threats to each other’s security."

But shortly after, tensions went on the rise again after Ankara said it had not received responses from Sweden and Finland on the extradition of members of the PKK and the organization of Islamic preacher Fethullah Gulen (FETO), deemed "terrorist" by Turkey.

Only Turkey and Hungary remain as the two sole NATO members who have not yet approved the membership of the two Scandinavian countries. 

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