OSLO (Reuters) - Norway’s public prosecutor ordered on Wednesday the release of an Iraqi Kurdish imam after Italian authorities withdrew a year-old extradition request linked to suspicions he had plotted attacks.

Mullah Krekar gestures next to lawyer Brynjar Meling (L) in Oslo's District Court, Norway, November 13, 2015. REUTERS/Cornelius Poppe/NTB scanpix

Mullah Krekar, the one-time leader of the Ansar al-Islam militant group, was arrested in Norway in November 2015 as part of a series of arrests across Europe. Italian prosecutors later asked for his extradition.

But Norway’s Director of Public Prosecutions (DPP) said Italian authorities had withdrawn the request for the cleric’s extradition, without clearly explaining the reasons.

A DPP statement said it was “ordering the release of Mullah Krekar.”

Prime Minister Erna Solberg bowed to the ruling on Krekar, who has been a thorn in the side of successive Norwegian governments. “This is something we have to accept,” she told a news conference, saying it was not up to politicians to decide.

Though deemed a threat to Norway’s national security, Krekar has not been deported to Iraq because authorities there could not guarantee he would not be executed.

Last week, Norway’s Supreme Court had approved the extradition to Italy of Krekar, who came to Norway as a refugee from Iraq in 1991 and has spent several periods in jail. [nL8N1DO26L]

Last year, Italian authorities said that at least 15 suspected members of a militant Islamist group including Krekar were arrested in six European countries, accused of planning attacks in Europe and the Middle East. [nL8N1373DH]

Krekar’s arrest last year took place in prison, where he was already serving an 18-month sentence for making death threats against a Kurdish man and giving an interview in which he encouraged other people to commit criminal acts.

Norway’s DPP said the letter from Italy’s justice ministry sent on Nov. 25 said an Italian court ruling in March had voided the basis for extradition.

The DPP said the Italian letter did not explain the March ruling nor say why it had taken so long to withdraw the extradition request.