The 63-year-old Iraqi Kurdish man – known as Mullah Krekar, but named Najumuddin Faraj Ahmad – was arrested in July 2019 after he was convicted in his absence by an Italian court and sentenced to 12 years in prison.
The Italian court found him guilty of having led a now dismantled jihadist network, Rawti Shax, a Kurdish movement with alleged links to the Islamic State group and which is suspected of planning attacks in the West.
Krekar arrived in Norway in 1991 as a refugee.
The Norwegian judiciary, including the Supreme Court, has authorised the extradition, requested by the Italian authorities in July 2019, three times and the Norwegian justice ministry on Wednesday gave final authorisation to move forward.
“The ministry considers that the conditions for an extradition to Italy are met,” Minister of Justice Monica Mæland said at a brief press conference.
Krekar now has three weeks to file an appeal to the country's King in Council, a special cabinet meeting on matters of importance where the King attends.
“There will be an appeal. I am already working on it,” Brynjar Meling, Krekar's lawyer, told AFP.
“This is a sad day for the rule of law in Norway and for justice minister Monica Mæland. It is obviously a wrong decision,” he added.
According to Meling, who is also considering taking the case to the European Court of Human Rights, there is no evidence indicating that his client was guilty.
Extraditing Krekar would remove a thorn in Norway's side, after Olso tried to deport him since 2003, believing him to be a threat to national security.
Krekar, who founded the radical Islamist group Ansar al-Islam, is designated a terrorist by the UN and the US and has spent several years in Norwegian prisons for issuing threats and calling for murder.