According to a report in the "Neue Osnabrücker Zeitung" newspaper published on Thursday, the number of people in Germany considered by authorities to be at risk of becoming Islamist terrorists is on the rise.

Citing numbers from the Federal Criminal Police Office (BKA), the paper reported that there are currently 657 people believed to be capable of carrying out a terror attack. According to the BKA, this number has quadrupled since the start of the war in Syria.

Many regarded as potential threats are being monitored by police, and around 100 are currently in jail. In addition, there are 388 "relevant persons" who could be considered at risk of lending assistance to perpetrators of terrorist acts.

Part of the reason for the dramatic rise in the number of potential terrorist in Germany is achange in how such evaluations are made, the newspaper said. Following an attack in December that saw a man drive a truck into a crowded Christmas market, authorities across Germany now use the same system for evaluating a person's potential threat. Previously, states had used varying definitions of what constitutes a threat.

In addition, fewer German citizens are leaving the country to join the so-called Islamic State (IS) in Syria or Iraq and considering attacks closer to home instead. According to authorities, this can be contributed to the fact that IS is being militarily weakened and fighting for them is a less attractive option.

Despite the drop, the BKA also reports that it has registered 920 people who have left Germany for Iraq or Syria. Around 70 are reported to have taken part in fighting or in training camps, with an additional 145 killed.