An assassination attempt on German Chancellor Angela Merkel has reportedly been foiled here as Czech police detained an armed man who tried to join her motorcade during visit to the capital.

"The perpetrator has been detained," the Mirror quoted police spokesman Josef Bocan as saying on Thursday.

"He is suspected of attempting to cause a crime -- specifically an attempt to use violence against an official," he said.

"The incident is currently being investigated by Prague detectives."

Merkel, who was in Prague to meet Czech Prime Minister Bohuslav Sobotka, was travelling from the airport to the city when the suspicious Black Mercedes appeared.

The driver refused to obey orders coming from the police cars accompanying the German Chancellor.

The suspect tried to enter the motorcade and cut off a police vehicle that was trying to stop him. He only stopped and got out of the vehicle after the police warned of shooting him.

The incident comes as Europe remains on high alert after a series of terror attacks over the past 12 months.

France, Germany and Belgium have been attacked by the Islamic State (IS) militant group, claiming hundreds of lives.