More than four years after Russia's full-scale invasion of Ukraine, European nations worry Moscow could escalate the conflict there and beyond, targeting Kyiv's supporters.
Western leaders have warned of a surge in Russian covert operations across Europe, amid concerns such activities could eventually cause casualties.
At the weekend, President Vladimir Putin's party won a record supermajority in Kremlin-choreographed parliamentary elections, after he cast the vote as a show of support for the war.
Some analysts believe the Kremlin chief may be laying the groundwork for further escalation, including another mobilisation drive. Here is the state of play:
Russia has not eased its maximalist demands, with the Kremlin still seeking full control of Ukraine's eastern Donetsk region.
But widespread drone use at the front has made large-scale troop movements almost impossible, preventing either side from gaining a clear advantage.
Russian forces are losing momentum in eastern Ukraine, Western officials say.
"We are still assessing that Russia has got a number of significant challenges on the battlefield," one said.
In April and May, Russian forces lost more ground in Ukraine than they captured, according to an AFP analysis of data from the US-based Institute for the Study of War (ISW). Russia's advance gained pace in August but remained far slower than in previous years.
For months, both sides have stepped up long-range strikes on civilian and industrial targets, including energy, transport and port infrastructure, as well as ships in the Black Sea.
Russian and Ukrainian military losses remain among the war's closest guarded secrets.
France's armed forces chief Fabien Mandon estimated in August that between 30,000 and 35,000 Russians are killed or wounded in combat every month.
Moscow has sought to bolster its ranks through generous enlistment bonuses for volunteers, the recruitment of fighters from Africa and Latin America, and the deployment of an estimated 30,000 to 50,000 North Korean troops behind the front lines in Russia.
But the gap between Russia's casualties and the number of people it can recruit is around 6,000 a month, a Western official said, requesting anonymity.
Putin has ruled out a repeat of the mobilisation that prompted an exodus of Russian men in September 2022.
"Putin is losing step by step his popularity," said Russian political scientist Nikolai Petrov.
He said the Russian leader may still "do something in order to escalate and in order to radically change the character of the war."
But "this cannot be achieved easily by mass mobilisation."
Donald Trump's mixed signals on Russia have complicated Europe's push for peace.
Earlier this month, the US president sent envoys to Moscow and Kyiv hoping to revive long-stalled peace talks. He has signed a bill authorising sweeping new sanctions designed to pressure Russia, but also chastised Ukraine for hitting Russian oil refineries.
"No one knows how the US president would react in the event of an attack -- whether direct or hybrid -- against a NATO member state," French researcher Celine Marange said.
"This uncertainty is in itself a victory for Moscow."
Trump last week touted "major progress" towards a permanent US military base in Poland, even as his administration launches a formal review of its military presence in Europe.
Any withdrawal of US troops should be "as balanced as possible," Sweden's top military commander Michael Claesson said this summer, to avoid "vulnerabilities that could -- and would more likely -- more or less be exploited from a Russian perspective."
Western officials believe Russia is increasing clandestine operations across Europe.
The attacks have fallen below the threshold of open warfare, but have included drone flights near sensitive sites, airspace violations, cyberattacks and acts of sabotage. They are often hard to trace back to Russia, which has repeatedly denied involvement.
Berlin this month blamed Moscow after explosive-laden drones were discovered at Leipzig airport in August. Had they detonated, the attack would likely have caused human casualties.
"The consequences could have been tragic, with loss of life and massive material damage," President Emmanuel Macron told reporters Friday after briefing political leaders on security threats.
"That means the intention of the Russian military intelligence services was precisely that."
A senior European security official said Russia's intelligence services were likely to take greater risks.
"Moscow is intensifying its campaign below the threshold of open conflict," a Western government source said in late August.
David Cattler, a researcher at the Center for European Policy Analysis, said Russians "want it to be small enough that it doesn't trigger a conventional response."
"And they want it also to maintain sufficient ambiguity that nobody can conclusively state in public that it was them."
Europeans do not rule out Russia testing the West's willingness to act through a military operation against a NATO country, whether an airstrike or another kind of limited attack.
Citing intelligence assessments, Polish Prime Minister Donald Tusk warned last week that Moscow's plans included "strikes using drones and missiles on countries supporting Ukraine".
The aim, he said, was to weaken NATO's unity and to convince members "that Article 5 is more theoretical than practical."
Article 5 triggers assistance by NATO countries when a member is attacked. NATO says that this assistance may or may not involve the use of armed force.
Macron said Tusk's remarks were "well-founded and well-documented."
A European security source said such Russian plans existed, but spy agencies had not yet detected any intention to turn them into a reality.
