Police are on high alert ahead of Germany's traditional carnival celebrations this week after social media connected to the Islamic State militant group called for attacks targeting revellers in Cologne and Nuremberg,

Islamists have used social networks to call for attacks, including during the Cologne carnival, Martin Lotz, head of the Cologne police's carnival operations, told dpa. He said that these kinds of statement also aimed at unsettling the population and that the police's operational concept will be adapted again as the region prepares for days of festivities.

Ahead of Carnival celebrations kicking off in Germany on Thursday, the Islamic State militant group called for attacks targeting revellers in Cologne and Nuremberg.Islamists suspected of belonging to the so-called Islamic State have used social networks to call for attacks-- including on Cologne's upcoming Carnival celebration.