Turkish state media said an inquiry was launched following the release of footage showing an effigy of Erdogan hung outside Stockholm city hall.

Turkish prosecutors have opened an inquiry into an incident in Stockholm in which an effigy of President Recep Tayyip Erdogan was strung up,

state media said, adding further diplomatic strain to Sweden’s bid to win Turkey’s approval to join NATO.

Footage first shared on Twitter by the so-called Swedish Solidarity Committee for Rojava showed an Erdogan effigy hung by its feet outside Stockholm city hall with a few people standing by.

Swedish Prime Minister Ulf Kristersson told broadcaster TV4 on Friday that the act was “extremely serious”

and he considered it an act of sabotage against the NATO application. Police said they had no knowledge of the incident until it was over.

NATO member Turkey summoned the Swedish ambassador on Thursday over the incident, which comes after months of efforts by Stockholm to win Ankara’s backing for the bid