Among them are several imams, including the head of Pristina's Grand Mosque, Shefqet Krasniqi, local reports say.

Some 200 Kosovo Albanians have gone to fight in Syria and several have died.

IS is thought to have attracted hundreds of European recruits in its campaign to set up a "caliphate" in broad swathes of Syria and Iraq.

Kosovo police did not name those arrested, publishing only their initials, but said the operation had been carried out following threats and due to the importance of national security.

Many of those held were from Pristina, Prizren or the flashpoint town of Mitrovica.

Islamist leader Fuad Raqimi was detained after a raid on his flat, reports said.

US envoy Tracey Jacobson, in a tweet, praised Kosovo's "pro-active response against fighters and terrorism".

Last month, 40 people were arrested as police searched dozens of sites across Kosovo, including makeshift mosques thought to have been used as recruitment centres.

In common with other European governments, Kosovo is tightening up its laws to tackle the rise in jihadists travelling to the Middle East.

Germany announced on Friday that it would seek to prosecute anyone who tried to recruit for IS or spread the group's propaganda.

French MPs on Tuesday backed a new anti-terror bill that would enable the passports of potential jihadists to be confiscated.

Six people were detained in the Lyon area of France on Wednesday, including a 13-year-old girl, on suspicion of playing a part in sending young girls to Syria.

Several European countries are facing the phenomenon of teenage girls travelling to Syria.

One of two Austrian girls who had gone to Syria was reportedly killed this week.

Samra Kesinovic, 16, and Sabina Selimovic, 15, both of Bosnian origin, disappeared from their homes in Vienna last April, leaving a letter to their parents saying they wanted to "fight for Islam".

It is unclear which of the two girls had died.

Police in the southern Austrian city of Graz picked up another two girls last week who were set to leave for Syria.

IS is sometimes known as Isis or Isil.