Germany is "under fire" from Russia, the leader of Berlin's foreign intelligence agency told lawmakers on Monday in a public parliamentary hearing.
"We must not sit back and assume that a possible Russian attack will not come until 2029 at the earliest," said Martin Jäger, the chief of the Federal Intelligence Service (BND). "We are already under fire today."
The boundaries between peace and war are becoming increasingly blurred, said Jäger.
"At best, there is an icy peace in Europe, which can turn into hot confrontation at any time. We must prepare ourselves for further escalation of the situation," he said.
The president of the domestic intelligence service, the Office for the Protection of the Constitution, said Russia was the "main perpetrator in the preparation and implementation of acts of sabotage in Germany and other European countries."
Sinan Selen called Moscow's actions "undoubtedly aggressive, offensive and increasingly escalative."
The comments in the Bundestag - Germany's lower house of parliament - came after weeks of tensions on NATO's eastern flank following several Russian violations of alliance airspace.
Germany is also on edge after a series of drone sightings over critical infrastructure, including Munich Airport, that have widely been attributed to Russia despite Moscow's denials.
Defence Minister Boris Pistorius has cautioned on several occasions in recent weeks that Russia could be in a position to launch a military strike against NATO territory by 2029.
Selen warned that Germany is "a primary target for Russian activities in Europe," while Jäger said the country is "clearly target area number one in Europe for Russia at the moment."
The intelligence chiefs were speaking at a public hearing of the parliamentary control committee, which monitors the work of the federal intelligence services.
Jäger said the Kremlin wants to test the limits of the West by undermining NATO, destabilizing European democracies and intimidating societies.
"Europe - paralysed by fear and rigidity of action - is to be driven into self-abandonment," the intelligence chief said. Moscow's aim is to make Europe, a greater economic power, dependent on Russia, he added.
To achieve this, Russia is relying on the manipulation of elections and public opinion, propaganda, provocation, disinformation, intimidation, espionage, sabotage, airspace violations by drones and fighter jets, contract killings and the persecution of opposition members living abroad.
"None of this is new, but in their accumulation, these individual events represent a new quality of confrontation," Jäger said.
However, Russia is not the only foreign actor operating in Germany, the intelligence chiefs said.
Jäger pointed to China and Iran, while Selen warned the peace deal in Gaza will not end the threat from extremists in the Middle East.