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LONDON — With 755 staff ordered to leave positions at the U.S. Embassy and consulates in Russia, diplomats will face an unprecedented exodus as they are forced to comply with Vladimir Putin's ultimatum, according to experts.

“We are in uncharted waters here,” said James Nixey, head of the Russia and Eurasia Program at the Chatham House think tank in London. “No expulsion has ever happened to this extent before. This is totally unprecedented.”

Putin ordered the dramatic reductions in diplomatic staff on Sunday. On Monday, a Kremlin spokesman said the U.S. may cut local employees as well as diplomats.

Based on past experience, it will be locally hired staff who deal with less essential tasks in the U.S. missions — from general maintenance to support in the visa section — that will be the first to go.

“The spirit in ‘86 was that everyone mucks in, and I would bet a dollar to a doughnut that will be the spirit of the embassy now.”

These cuts will be very hard to implement, according to the American ambassador to Russia from 2012 to 2014, Michael McFaul, who recalled the difficulty of closing the U.S. Agency for International Development offices, with 70 employees, during his tenure.

“It’s going to be much harder to do our business in Russia as a result of this,” McFaul told TODAY’s Matt Lauer on Monday.

According to a 2013 State Department report, there are 1,279 workers among the U.S. Embassy in Moscow, three consulates general in St. Petersburg, Yekaterinburg, and Vladivostok and a consular agency in Yuzhno-Sakhalinsk.

Of those employees, 301 are U.S. hires and 934 are locally employed staff. Only U.S. hires have access to classified, confidential or other sensitive information.

Diplomatic staff with the political and economic sections, as well as American citizen services and defense attachés are considered essential and will remain largely unaffected by the decision, former diplomats said. They declined to comment when asked how the cuts — equaling some 60 percent of staff — could affect intelligence operations.

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Russians applying for visas to the U.S. will also be affected, with longer waiting times likely, experts said.

The Russian government “announced with great fanfare the decision to reduce staff and the impact will be throwing Russians citizens out of work,” said Steve Pifer, a former ambassador to the Ukraine.

"The expulsions will impact embassy operations, but I think that the U.S. staff will prove a lot more resilient and resourceful than the Russians think,” he said.

Pifer served at the U.S. Embassy in Moscow during the last mass expulsion of staff in 1986 so has a good idea of what diplomats there face now. At the time, all Soviet citizens were barred from working at the embassy — equaling some 250 jobs. The move was in retaliation for the U.S. expelling 55 diplomats from the then Soviet Union.

Within a day of the decision, embassy staff was on "all-purpose duty," said Pifer, who is now a senior fellow at the Brookings Institute.

Russian President Valdimir Putin has ordered the U.S. to cut its staff at the U.S. Embassy in Moscow, as well as at other diplomatic properties. Mladen Antonov / AFP - Getty Images

"That meant I had a normal job four days a week and one day a week I drove a truck, picked up diplomatic pouches and moved furniture," he said. “The spirit in ‘86 was that everyone mucks in, and I would bet a dollar to a doughnut that will be the spirit of the embassy now.”

The size of the cuts to the U.S. presence in Russia now far exceeds the sanctions imposed on Moscow in December 2016 by President Barack Obama for its meddling in the U.S. election. Then, the president expelled 35 Russian diplomats and seized two Russian properties — one in Maryland and one in New York.

At the time, Russia chose not to retaliate. That restraint ended when Congress voted to approve sanctions last week. However, Russia's options are limited when it comes to striking back against the U.S., said Pifer.

Related: What Went On in Russia's Shuttered U.S. Compounds?

“They don’t have possibility of announcing economic sanctions that will impact U.S. economy the way U.S. sanctions will impact theirs,” he said.

Compared to its counterparts, the U.S. generally has the largest diplomatic delegations in foreign countries.

While the U.S. mission in Russia is by no means small, it’s also not its largest in the world. U.S. missions in Iraq, Afghanistan and India all have more staff, according to Thomas Pickering, the former ambassador to the U.N., as well as Russia, where he served from 1993 to 1996.

In comparison, the Russian presence in the U.S. is more limited. Russia chose the number of staff to cut to bring the U.S. presence in Russia in line with the Russian presence in the U.S.

"Reciprocity is the watchword in diplomacy," said Pickering. "There was the perception of an imbalance" of staff between the two nations that's now being corrected.

For Putin, the tough line on the U.S. comes with the domestic advantage of being able to show his strength, especially with an election coming up in less than nine months.

“They are testing the waters and flying kites to see what they can get away with," said Nixey. "The answer is they can get away with quite a lot.”