Alfa Group Supervisory Board Chairman Mikhail Fridman attends the 2017 Atlases Russian Business Forum at the Crocus City Hall.Alfa Group Supervisory Board Chairman Mikhail Fridman attends the 2017 Atlases Russian Business Forum at the Crocus City Hall.

As Europe and the U.S. impose sanctions on Russia, some of Putin's inner circle have begun speaking out against him.

While none have directly referenced the Russian president, the rare sounds of dissent from his high-profile allies, many of whom have close ties to the Kremlin, signal the widening fissure among Russian voices.

The founder of Russia's largest private bank, Alfa Bank, became the first Russian businessman to speak out against the conflict on Friday.

In a letter to staff at his London-based private equity firm LetterOne, the Ukrainian native, whose parents still live in the country, said that war can never be the answer.

The current conflict is a tragedy for both the Ukrainian and Russian people, he wrote in the letter first seen by the Financial Times.

He said that he does not make political statements and that he is a businessman with responsibilities. War can never be the answer. The crisis will cost lives and damage two nations who have been brothers for hundreds of years.

The CEO of Veon told CNBC Monday that the war should be stopped as soon as possible.

He said that the company is providing internet access to Ukrainians fleeing the conflict.

The European Union placed sanctions on Fridman personally along with his business partner and other wealthy Russians.

Fridman said that he didn't know if there would be a backlash in Russia against the invasion, but that a blanket ban on Russians doing business in the world seemed unfair.

Mordashov said that the fighting should be stopped but that he should not be a target of international sanctions.

I have nothing to do with the current tensions. I don't understand why sanctions have been imposed against us.

The subject of U.S. sanctions, metals mogul Oleg Deripaska wrote on Telegram last week that peace is very important. Negotiations must start as soon as possible.

The billionaire founder of Tinkoff Bank, who is currently undergoing cancer treatment, described the conflict as "unthinkable and unacceptable" and called for states to spend money on cancer research.

The billionaire owner of the English soccer team has not spoken out publicly, but he gave the team to a charity. He was involved in talks in Belarus on Monday after Ukraine asked for his help in reaching a peaceful resolution.

The comments from Russia's wealthy elite join those of other high profile figures who have called for an end to hostilities.

They are not insignificant. The almost two decades since the imprisonment of Russia's richest man for funding opposition parties has not elicited a peep from any of the country's richest men.

Still, they are a handful among the wealth of Russian tycoons who have remained silent, and many have questioned their motives as they face potential further sanctions.

Some of Russia's ultra-rich have seen their net worth plummet, resulting in losses of $83 billion so far this year, as the Russian economy remains in freefall.

The powerful Russian leader has shown little sign of backing down despite defiance from within Ukraine and wide-reaching measures from its Western allies.