In the aftermath of an Iranian assassination attempt against an Iranian-Arab opposition figure on Danish soil, Denmark has called back its ambassador from Tehran and called for new European Union sanctions against the regime.

The assassination plot meant to target the leader of the Danish branch of the separatist Arab Struggle Movement for the Liberation of Ahwaz (ASMLA), Danish Foreign Ministry spokeswoman Anne Møller Ege said, CNN reported.

“The assessment is that an Iranian intelligence agency has planned an assassination on Danish soil,” said Danish Foreign Minister Anders Samuelsen on Tuesday. “This is completely unacceptable. In fact, the gravity of the matter is difficult to describe.”

“With regard to the man in custody, an investigation is ongoing,” said the Danish security service. “However, when PET now states that there is sufficient basis to conclude that an Iranian intelligence service has been planning the assassination of an individual living in Denmark, it is not only based on the case against the man in custody but on comprehensive intelligence efforts.”

This development comes after at least the second Iranian assassination attempt on European soil. In June, Iranian diplomat credentialed in Austria was allegedly part of a bomb plot at a Paris rally of Iranian dissidents.

Israeli officials said on Wednesday that the Mossad intelligence service tipped its Danish counterparts regarding the alleged Iranian plot.