Merkel, who was in the Czech Republic's capital for talks with Prime Minister Bohuslav Sobotka on Thursday, was traveling from the airport to the government headquarters when a man in a black Mercedes 4x4 "attempted to join the motorcade," police spokesman Jozef Bocan said.

"He tried to run down police securing the road," said Bocan, adding that officers had to use firearms to subdue the suspect.

Bocan was cited by Britain's "Mirror" newspaper confirming that man had been detained.

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

"Mirror" reported that the suspect failed to obey orders from police accompanying the chancellor's motorcade.

As he cut up a police vehicle that attempted to stop him, the paper said, police threatened to shoot him. He then gave himself up.

Suspect not armed

Police said the suspect acted alone and was not armed. But they believe some items found in his car could easily have been used as weapons.

Germany's "Bild" leading tabloid wrote the man was interrogated, but so far there was no indication as to a motive for his actions.

Police didn't identify the driver either, "Bild" added.

Germany remains on high alert following several violent attacks last month, some carried out by migrants in the name of "Islamic State" (IS) militants.

Those incidents followed several deadly attacks in France and Belgium over the past 18 months.

Anti-migrant protest

During Merkel's trip several hundred protesters, including members of anti-Islam groups, rallied in central Prague against the German leader's decision to open the EU's doors to refugees last summer.

Many Czechs say the move exacerbated the migrant crisis, which left many European countries struggling to assimilate thousands of migrants.

A leader of Germany's anti-Islamic, anti-immigrant Pegida movement, Tatiana Festerling, was also present for the demonstration.

Merkel held talks with Sobotka and President Milo Zemen focused on the migrant crisis, and the future of the European Union after Britain's decision to leave the bloc.

East European countries including the Czech Republic, Hungary, Poland and Slovakia have refused to take in refugees under an EU-wide quota system which Merkel has championed.

Sobotka insisted his country "cannot endorse as system that calls for mandatory quotas to distribute refugees," during a joint press conference with Merkel.