Five top Muslim clerics, including a school chancellor, have been arrested in a series of raids linked to suspected extremism in Sweden.
It comes as the Swedish authorities have faced domestic and international criticism for failing to arrest and prosecute returning ISIS fighters and suggestions that the country could be viewed as a sanctuary for terrorists.
The crackdown comes as the Swedish government seeks to bring in tougher laws to target extremists.
In a month long series of raids Swedish security service Sapo have arrested three Imams, the head of one of the country’s leading state-funded Islamic schools and one of the Imam’s sons.
Many of those arrested have previously been refused Swedish citizenship over the last decade.
Chief executive of the Vetenskapsskolan school in Gothenburg, Abdel-Nasser El Nadi, was the latest person to be arrested last week.
He has reportedly been taken to an immigration detention centre.
The other arrested men include Abo Raad, imam of a mosque in Gävle, and his son, Hussein Al-Jibury, imam of a mosque in Umeå, and Fekri Hamad, imam of a mosque in Västerås.
Sapo has declined to comment on the arrests or its investigation.
Mr El-Nadi, who was born in Egypt, has lived in Sweden since 1992 and has twice been rejected for citizenship.
Last year under his leadership the school was criticised by the Swedish School Inspectorate for not sufficiently promoting equality between girls and boys.
There are 11 Muslim schools in Sweden which are all funded by the state.
Officials have been focusing on issues in Gothenburg as more than a third of Swedish ISIS fighters are believed to have come from the city.
Latest figures from Sapo reveal at least 300 of its citizens travelled to Syria and Irag between 2012 and 2017 to join extremist groups.
It is believed half have returned, 100 are still fighting and 50 have been killed.
Sweden is the largest exporter of ISIS fighters per capita in Europe.
Under Sweden’s present terror laws it is not illegal to be part of or to assist a terrorist organisation.
The proposed law to make this illegal is presently being considered but would not be introduced until August at the earliest and would not be applied retrospectively.
It comes as Sweden’s interior minister Mikael Damberg has visited Britain and a number of EU countries to gain support for a proposal to create a war crimes tribunal dedicated to dealing with the prosecution of ISIS fighters.
“People from around the world travelled to fight with [Isis] in Syria and Iraq. This is an international issue requiring a united response,” he told the Financial Times.
“We want to see foreign fighters brought to trial in the most appropriate jurisdiction, which will often be in the region where offences have been committed, and will work with our international partners in pursuit of this.”
The summit will be held in Stockholm next month to discuss the plans with world leaders.
It will be looking at establishing a tribunal in Iraq and adopting a similar model to the international courts established to prosecute perpetrators of the genocides in Rwanda.
Sweden’s war crimes unit is presently prosecuting five alleged ISIS fighters.
