A Moscow deadline for almost two-thirds of U.S. diplomatic staff to leave Russia expires on Friday, an exodus that starkly demonstrates the souring relationship between Vladimir Putin and Donald Trump.
There were hopes of improved ties between Moscow and Washington after Trump's election to the U.S. presidency last year, when both leaders showered each other in praise.
But after the U.S. Congress approved new economic sanctions against Russia over Moscow's alleged meddling in the November election, Putin in July ordered the drastic embassy cuts in retaliation.
Putin said 755 diplomatic staff -- both Russian and American -- would have to stop work by September 1, although the U.S. State Department has not confirmed the number.
The number of U.S. diplomatic staff will now be capped at 455, the same number that Russia has in the United States.
"We have waited long enough, hoping that the situation would perhaps change for the better," Putin said when he announced the cuts.
"But it seems that even if the situation is changing, it's not for any time soon."
Trump only reluctantly signed off on the Congress-backed sanctions, describing them as "significantly flawed" and partially unconstitutional.
"Our relationship with Russia is at an all-time & very dangerous low," he tweeted.
Russian Prime Minister Dmitry Medvedev said on Twitter the sanctions demonstrated Trump's "total weakness" and amounted to a "full-fledged trade war".
It is not clear how many of the 755 staff losing their jobs will be physically leaving the country, or how many are Russian citizens. The RBK news site cited sources saying that at least 600 are Russian.
The head of a firm servicing the Russian diplomatic corps, Alexei Izotov, said some former U.S. embassy technical staff are applying for work and "have been added to the database".
'It could have been love'
"It could have been love between Trump and Putin. Hope remained until the latest sanctions were passed but it seems Russian authorities have come to the conclusion that Trump is hopeless," said political analyst Andrei Kolesnikov of the Carnegie Moscow Centre.
"Neither Putin nor Trump know how to build such a relationship. They don't have a strategy or a real topic of conversation except technical questions about Syria."
While Trump has put a stop to U.S. support for Syrian rebels, to the Kremlin's great satisfaction, he has fundamentally changed his thinking on other contested areas, digging in his heels over the Ukraine conflict, Moscow's annexation of Crimea and NATO's expansion in eastern Europe.
During a trip to Kiev last week, Pentagon chief Jim Mattis vowed to continue helping Ukrainian armed forces as they battle pro-Russian rebel fighters.
Trump himself has stressed his desire to "move forward in working constructively" with Russia, including on cyber security to prevent hacking of future elections. His own team, however, has been sceptical over any moves to draw closer to Moscow.
The United States this month complied with a demand from Moscow to stop using a Russian country house and a storage facility.
The request came as a response to a U.S. move to close access to two compounds used by Russian diplomats last year, a move that caused much bitterness in Moscow.
'Total impasse'
In another retaliatory move, Washington announced it would suspend the issuing of all non-immigrant visas in Russia between August 23 and September 1.
Visa operations at U.S. consulates will remain suspended indefinitely.
Russian foreign ministry spokeswoman Maria Zakharova called the decision "genocide of the common people" in an interview released Monday by independent Dozhd television channel.
"The war of sanctions and counter-sanctions has got a new lease of life," political analyst Kolesnikov said, and sanctions have now become "the only way to demonstrate discontent."
Noting the current state of relations, Moscow has appointed a hawkish new ambassador to Washington, Anatoly Antonov, known as a hardliner and a tough negotiator with a deep suspicion of the United States.
"No one pays attention to Trump any more," said Kolesnikov. "All that remains is a battle between the Russian authorities and the U.S. establishment.
"The situation is mired in a total impasse."