“People saying hello and greeting me is never something that particularly affects me,” Scholz said when quizzed on the incident at a press conference in Estonian capital Tallinn.

“That’s very normal and I didn’t find this situation dramatic either,” Scholz said of the surprising encounter on Wednesday evening.

But the mistakes which allowed the man to approach the chancellor unimpeded have caused consternation among security officials.

Driving a dark-coloured Audi, the man was able to join Scholz’s convoy on its way to Frankfurt airport, following an event at the European Central Bank celebrating its 25-year anniversary.

After slipping past airport security, the man climbed out of the vehicle to shake the chancellor’s hand and put his arms around Scholz.

“An incident like this must not be allowed to happen,” Interior Minister Nancy Faeser said on the sidelines of an event with her Czech counterpart at the border between the two countries.

“Those involved will now work out precisely what happened, where mistakes were made, in order to avoid them in the future,” Faeser said.

The Federal Criminal Police Office (BKA) is usually responsible for the security of the chancellor, while regional police were also in support on Wednesday.

Scholz himself defended the work done by those responsible for his protection.

“The police do a good job, I feel safe,” he said.

Authorities have opened an investigation into the man who approached the chancellor, to assess whether his actions were criminal, the interior ministry said.

The chancellor’s security detail did not immediately notice the breach, German weekly Spiegel reported. The man had time to return to his car and light a cigarette before he was arrested by police.

Scholz’s assailant subsequently tested positive for drugs, according to Spiegel.