"I think we have hit an inflection point in the current administration’s approach towards Russia," said a diplomat who spoke on condition of anonymity. "There has been a shift in balance."

The diplomat attributed the evolution partly to a clash between US-backed and Russian-backed forces in the Syrian city of Deir al-Zor in February; Russia pounding Syria's eastern Ghouta enclave of anti-government rebels with air strikes during the past month; and Putin showing a video on March 1 of a weapon appearing to hover over what looked like a map of Florida, home to Trump's Mar-a-Lago resort.

"Those three things, taken together, have caused a shift in analysis in parts ... of the administration," said the diplomat.

Other Russia analysts said it was not clear whether Trump had fundamentally changed his stance.

The sanctions come after more than a year of criticism from Democrats and some Republican lawmakers that Trump has been too slow to act against Russia for intruding in the election.

The sanctioned individuals include Yevgeniy Prigozhin, a wealthy Russian known as "Putin's chef," whom Special Counsel Robert Mueller alleged controlled the troll farm through two other businesses.

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The Russian ruble fell to a session low in trading after the list was posted.

The Treasury Department also announced sanctions against Russia's Federal Security Service, a spy organisation know as the FSB, and its Main Intelligence Directorate, a military intelligence service known as the GRU. Igor Korobov, described as chief of the GRU, was also sanctioned, along with five other past or present senior GRU officials.

The two agencies and most of the officials had been previously sanctioned under the Obama administration.

The GRU was "directly involved" in meddling in election through cyber attacks and was "directly responsible" for the 2017 NotPetya cyber attack, Treasury said.

The statement also cited malicious cyber attacks by the FSB including a 2014 hack that compromised millions of Yahoo accounts.

"The Administration is confronting and countering malign Russian cyber activity, including their attempted interference in US elections, destructive cyber attacks, and intrusions targeting critical infrastructure," Treasury Secretary Steven Mnuchin said in a statement.

"These targeted sanctions are a part of a broader effort to address the ongoing nefarious attacks emanating from Russia."

Eugene Rumer, a former US national intelligence officer for Russia, suggested Trump's approach may ultimately be guided by Mueller's investigation.

"My hypothesis is ... the White House stance on Russia is going to be determined to a large extent by how much they think the investigation threatens their political position," Rumer said.

Officials from multiple US agencies discussed next steps at a meeting on Thursday, with one aim being to avoid personally attacking Putin and taking in-your-face steps that could prompt retaliation.

Bloomberg, Reuters