Warning: Russia could open "second theatre of war"

Germany's chief of defence has urged the West not to underestimate Moscow's military strength. 

"The bulk of the Russian land forces may be tied down in Ukraine at the moment but, even so, we should not underestimate the Russian land forces' potential to open a second theatre of war," warned General Eberhard Zorn, the highest-ranking soldier of the Bundeswehr, Sky News reports. 

Russia also has a navy and air force at its disposal beyond the army, he added. 

"Most of the Russian navy has not yet been deployed in the war on Ukraine, and the Russian air force still has significant potential as well, which poses a threat to NATO too," he said.

The Bundeswehr regularly supports NATO air policing missions over the Baltic states with fighter jets.

General Zorn said Russia would be "very well capable" of expanding the conflict