ROME (Reuters) - Police in six European countries arrested at least 15 suspected members of a militant Islamist group that was planning attacks in Norway and the Middle East, Italian authorities said on Thursday.
They said the militants planned to strike Norwegian and British diplomats in the Middle East and politicians in Norway but gave no further information about the potential targets or the time frame for any attacks.
Police in Oslo said there had never been a "concrete or acute threat" against any Norwegian citizens or interests.
Italian Interior Minister Angelino Alfano said preventative measures had worked, but no country was immune.
"Our country is exposed to the risk of international terrorism because we are part of the broad international coalition that is fighting (Islamic State's self-proclaimed) caliphate," he said.
The early-morning raids targeted the Rawti Shax group, which police said was a Kurdish Sunni Muslim association dedicated to overthrowing the government of Iraq's Kurdistan region and installing rule by sharia, the Islamic code of law and morals.
Italy's national Carabinieri police led the investigation, with security forces in Italy, Britain, Norway, Finland, Germany and Switzerland taking part in Thursday's swoop.
Rawti Shax, which means "The New Course", also has cells in Greece, Sweden, Iraq, Iran and Syria, according to the European Union's judicial cooperation unit Eurojust.
"This was an incredibly difficult and complicated investigation that has been going on for five years," said prosecutor Franco Roberti, the head of Italy's anti-mafia and anti-terrorism unit.
A total of 17 arrest warrants were issued, almost all for Iraqi Kurds, and 15 suspects were picked up immediately. One of those wanted was believed to be in Iraq, while it was not yet clear whether another suspect had been found in Switzerland.
All of them face international terrorism charges, the Carabinieri said in a statement.
As well as the arrests, authorities in the various countries searched 26 premises and seized electronic devices and documents, Eurojust said in a statement.
Among the suspects was Mullah Krekar, the one-time leader of the Ansar al-Islam militant group. He received his arrest warrant in a prison in Norway where he was already serving an 18-month term for making death threats against a Kurdish man and encouraging others to commit criminal acts in a TV interview.
Krekar went to Norway as a refugee in 1991 and had earlier been deemed a threat to national security. However, Norwegian authorities did not expel him to Iraq because authorities there could not guarantee he would not be executed.
Italy said it would now seek to extradite him.
His lawyer Brynjar Meling told Norwegian news agency NTB he saw no grounds for this, adding that Krekar considered the charges "a rehash of old stuff".
Italian investigators say Rawti Shax was rooted in Europe and communicated via the Internet, providing logistical and financial support to send fighters to Syria and Iraq.
Meling said his client had been in jail for all but one month since early 2012 and did not have Internet access.
Rome prosecutor Giancarlo Capaldo said Rawti Shax, which also went by the name Didi Nwe (Towards the Mountain), aimed to train the fighters for future conflict in Iraq's Kurdistan.
"During the course of our investigation, we saw some fighters leave for Syria and die in the conflict," Capaldo said.
Additional reporting by Steve Scherer, Philip Pullella, Gwladys Fouche and Nerijus Adomaitis; Writing by Crispian Balmer and Isla Binnie; Editing by Tom Heneghan