Muslim militants have made appeals for attacks against the Euro 2008 football championships on jihadist websites which worry Swiss police but they said there was no "concrete" threat yet.

The championships in Switzerland and Austria start on 7 June and Swiss federal police spokesperson Juerg Buehler told La Liberte daily that the tournament "is a target cited by the Islamist terrorist network" on websites.

"We are following the situation very closely," he said.

He told La Liberte that similar threats were made before the World Cup in Germany in 2006, and that some attacks were planned against the rail network but were called off because security was considered too tight.

"We are prepared for every eventuality," he said.

In a statement sent to AFP however, Swiss police said:"Any big event like Euro 2008 could be a target of choice for terrorists... but there are no concrete elements right now that would lean one to fear any specific danger."

No extremist group has given any indication that it will target the football championships, police added.

"It is clear however that how things develop in the coming weeks and months in global hotspots could have security repercussions at home," the statement said.

La Liberte said appeals for attacks had grown on websites known to be used by followers of Osama bin Laden's al-Qaeda and other militant groups.

It said Switzerland is widely accused of Islamophobia in the Muslim world, notably because of opposition to the construction of mosque minarets in several Swiss cities.

Austria could be a target because of the presence of its troops in the international force in Afghanistan.

Counter-terrorism experts say Islamist forums regularly carry threats of attacks which have to be studied though few are to be taken seriously.

AFP