Germany on Tuesday blamed Russia for an attempted "hybrid attack" involving an explosive-laden drone at a strategic airport last month and announced diplomatic counter-measures.
The European Union expressed "full solidarity" with Germany, NATO assured that it would defend its members and countries including Britain, Estonia and Poland offered strong backing.
Germany will close Russia's consulate in the former capital Bonn later this month, and cancel the contract for the Russian House, a cultural center in Berlin, said Foreign Minister Johann Wadephul.
"We are tightening entry controls for Russian nationals" and Germany would propose the listings of more Russian individuals for European Union sanctions, he added, as the Russian ambassador to Berlin was being summoned.
Germany's top diplomat also vowed that "we are increasing pressure on the Russian shadow fleet" -- a term for the old oil tankers and other cargo ships with opaque ownership Russia uses to get around Western sanctions.
Interior Minister Alexander Dobrindt said that after assessing the drone technology used and other intelligence, "the government concludes that Russia is responsible for the hybrid attack in Leipzig on August 4".
He blamed "low-level agents" for the operation and said "the drone configuration -- various components, explosives and ignition systems -- are known to us from other hybrid operations by Russia and its war against Ukraine".
"We do not view the Leipzig incident in isolation, but rather see it in the context of other hybrid actions," he said. "We assume that Germany is the target of further hybrid attacks by Russia."
"We are not at war, but we are a daily target of hybrid warfare."
European Union chief Ursula von der Leyen said the bloc stands in "full solidarity" with Germany, while NATO chief Mark Rutte said the alliance "will continue to strengthen our ability to deter and defend all Allies against any threat."
Germany, which supports Ukraine in its fight against Russia, has for months reported suspicious drone sightings over military and industrial sites, but the Leipzig incident raised the alarm as a drone found there carried explosives.
Police used a robot to defuse the device near a Ukrainian cargo plane. Another drone was reportedly found weeks later near the airport, also with traces of an explosive substance.
The airport in eastern Germany plays a key role in the transport of military goods, including by the German military and NATO allies, and also serves as a base for Ukraine's Antonov Airlines.
- 'Hub for espionage' -
Chancellor Friedrich Merz said last week that Germany has "found itself in the crosshairs of hybrid attackers" and warned that the perpetrators would "pay for them", without naming a target.
There had been much discussion of whether Germany should shut down Berlin's Russian House, which security services believe is both a center to spread propaganda and an intelligence hub.
The Russian House of Science and Culture, a seven-storey building opened in 1984 in what was then East Berlin, is located near the Russian embassy.
Conservative MP and security policy expert Roderich Kiesewetter recently told Welt TV that the facility is assumed to be a hub for espionage.
He said more than 100 people lived there "with no one knowing who they are" and that the building's power consumption is unusually high.
It was "presumably filled with technical surveillance equipment", he said, and used by "people who are not well-disposed toward Germany".
In recent weeks, the German government had explained it was so far keeping the Russian House open by pointing to its bilateral contractual link to the Goethe Institute in Moscow.
Kiesewetter had dismissed concerns about Russian countermeasures.
"Are we not closing it because we believe the Goethe Institutes in Russia would then be closed in retaliation?" he asked. "Then they'll just get closed."
