BERLIN (Reuters) - The German military will establish a new division tasked exclusively with territorial defence, the army said on Saturday, bringing all existing reserve units under direct army command.

The reorganization will take effect in April and raise the number of German divisions - units of some 20,000 troops - to four without increasing the total number of around 180,000 soldiers in the German forces.

"The territorial defence will be put under army command from April 1, 2025," an army spokesperson said, confirming a report by German news agency dpa.

The Western military alliance NATO is at its highest alert stage since the Cold War, with its more pessimistic officials, including German Defence Minister Boris Pistorius, saying that an attack by Russia on its borders could happen within four years.

The German move will streamline command structures in territorial defence at a time when what Berlin describes as acts of Russian sabotage against the country's critical infrastructure have reached a new high. Russia denies the accusations.

So far, Berlin has three divisions that NATO can call upon in case of a conflict, whose main job will be defending the alliance by confronting an adversary right at the front lines.

The fourth division will be tasked with Germany's defence at home, including the protection of infrastructure such as ports, railways and supply and deployment routes.

Germany is gearing up for its role as major logistics hub in any conflict with Moscow, with tens of thousands of reinforcement troops from other NATO allies expected to be deployed east through Germany after arriving at its North Sea ports.

(Reporting by Sabine Siebold; Editing by Angus MacSwan)