Security threat 'very high' from German far-right: Interior minister

German interior minister Horst Seehofer said Friday that the police presence would be increased across the country to counter the "very high" security threat from the far-right after a gunman killed nine people in a racist attack late Wednesday.

"The security threat from right-wing extremism, anti-semitism and racism is very high," Seehofer said at a press conference in Berlin.

He also announced an "increased police presence" and "increased surveillance" at mosques, train stations, airports and borders.

Right-wing extremism, Seehofer said, was the "biggest security threat facing Germany", and one which had left "a trail of blood" behind it in recent months.

Germany has already taken several measures to combat right-wing extremism after a string of violent incidents over the last year.

Last June, pro-migrant politician Walter Luebcke was murdered, while October brought an attack on a synagogue in the eastern city of Halle.

Suspects in both cases have ties to the far-right scene.

Seehofer said he was not calling for more police officers or further laws, but rather "greater use of the options already available to us".

Sitting to his right, Justice Minister Christine Lambrecht said the government would examine in detail how firearms could end up in the hands of "extremists".

Yet both Seehofer and Justice Minister Christine Lambrecht underlined the difficulty of detecting attackers who act alone, as the key suspect in the Hanau shootings appeared to have done.

"Despite all our efforts, we cannot completely rule out such terrible crimes," said Seehofer.

Federal police chief Holger Muench, meanwhile, warned that "around half" of those who carry out such attacks were previously unknown to the authorities.