NEW YORK—Ketchum’s controversial PR assignment for Russia, a relationship that has spanned nine years, has ended in the US and Europe.

It is understood that the assignment, once lucrative, has dwindled in size and scope in recent months, amid heightened international tensions over the Ukraine crisis, which has seen Russia face sanctions and grapple with a struggling economy.

"Ketchum no longer represents the Russian Federation in the US or Europe with the exception of our office in Moscow," said Ketchum in a statement. "Our partner in the consortium, GPlus, continues to operate under the terms of the contract."

A lengthy Forbes Russia article last year revealed the pressures on the relationship as the Ukraine crisis escalated. One executive familiar with the situation told the Holmes Report that the end of the assignment was, ultimately, an unsurprising conclusion amid the current geopolitical situation.

"We decided not to renew the contract because of the anti-Russian hysteria, the information war that is going on," Putin's spokesman Dmitry Peskov told CNNMoney.

"If you spend a lot of money on communication, you want it to be fruitful — and that is not possible in this hateful environment," added Peskov.

Much of Ketchum's work, such as the ThinkRussia website, involved showcasing the country's appeal as an investment destination. That positioning has proved difficult to maintain as Russia's economic woes have mounted.

Ketchum first began working for Russia in 2006, supporting the country's hosting of the G8 Summit that year. The lucrative relationship has netted the firm as much as $25m but also attracted considerable mainstream media scrutiny.

Those concerns did not stop Ketchum successfully defending its global PR remit in 2012, before placing a Vladimir Putin op-ed in the New York Times in 2013.

However, the onset of the Ukraine crisis last year forced Ketchum to clarify its role on the business, even as account activity decreased. Department of Justice filings revealed a sharp downward spike in fees for the most recent six-month reporting period, ending 30 November, 2014.

Ketchum's Moscow operation, led by Michael Maslov, has close links to some of Putin's top advisors, and will continue its relatively limited work for the Russian Government.

The firm's relationship with Russian energy giant Gazprom ended in the US last year, although work continues in Europe and Asia, where the company is focusing its efforts.