"Being the ambassador to Russia was probably the hardest assignment of my career," Lynne Tracy, who represented the US in Moscow from 2023 and 2025, tells the BBC.
US, UK and European diplomats once played a crucial role in Russia, defusing tensions even at the worst moments of the Cold War.
But now, deemed "unfriendly" by President Vladimir Putin's government, Western ambassadors are under constant surveillance, isolated and increasingly cut off from the country they were sent to understand, as the war in Ukraine grinds on through its fifth year.
The BBC has spoken to five diplomats who have served in Russia since it launched its full-scale invasion.
They compare current pressure levels to the Cold War era - when Western embassies were monitored through physical surveillance, listening devices hidden inside gifts, and "spy dust" - a near invisible chemical agent used to track officials.
Hundreds of Russian diplomats were expelled from countries in Europe and the US after the war began in 2022. Moscow responded in kind, declaring hundreds of Western diplomats persona non grata and leaving many embassies short-staffed.
Tracy's 30-year career took her to countries like Pakistan, where she survived an armed attack in 2008. But she says that even under constant physical threat, her posting in Peshawar was, in a sense, easier than Russia.
"There, I still felt that there were things within my control. What made Moscow more difficult were the high levels of uncertainty."
The constant pressure from Russian counterintelligence was the primary source of such uncertainty, she recalls.
Russian diplomats in the West also complain of such unfair treatment. But according to the diplomats who spoke to the BBC, the scope and tactics of Moscow's intelligence services are far greater.
"Expect listening devices, expect cameras in every single room of your house," a former European diplomat says of the warning he received before leaving for Moscow.
Another ex-ambassador says they were forced to dismiss two Russian employees after Moscow's domestic security service, the FSB, tried to recruit them, demanding that they report on everything going on at the diplomatic mission.
The pair told the embassy instead, who let them go - "otherwise, they could have faced some sort of criminal prosecution".
Meanwhile, Russians who would ordinarily build relationships with diplomatic staff - such as those working in academia and culture - are also being intimidated into avoiding contact with Western officials.
One former ambassador says his guests were once "tailed" by FSB agents right up to the doors of the embassy.
Russian officials make little secret of their attitude towards Western diplomats. They have openly accused those from "unfriendly countries" of engaging in "espionage".
Moscow has been particularly critical of those who show an interest in expressions of dissent against the Kremlin and, according to Russian journalist Alexei Venediktov, has effectively banned most Russian officials from speaking to Western embassies.
This has only worsened relations with the West, says Venediktov, who recalls telling Russian officials: "You are being misunderstood precisely because of your own actions - because ambassadors cannot do their jobs."
Today, Moscow has little to no contact with many Western governments, says one ex-European ambassador. "There are no calls, no meetings at ministerial level."
But they say this has made diplomats all the more important, left with the responsibility to communicate their governments' positions to Moscow.
"Generals prove what they can do during a war. The same is true for diplomats. When things get really difficult, every single thing you do actually matters."
Lynne Tracy left Moscow in 2025 feeling she had accomplished her primary mission: the US Embassy had held firm.
But she is also proud of the work she and her team did to maintain connection between Americans and ordinary Russians.
"Because at some point, government-to-government relations will have a chance to improve - and those ties between people will be there to help speed the improvement."