WASHINGTON (REUTERS) - By imposing new sanctions on Russia and condemning a suspected Russian chemical attack in Britain, Washington has hinted at a tougher stance toward Moscow despite President Donald Trump's stated desire for better ties.

The US Treasury slapped sanctions on 19 Russian citizens and five entities for election meddling and cyber attacks in the most significant steps the United States has taken against Russia since Mr Trump took office amid US intelligence agency allegations that Moscow tried to help him win the 2016 election.

While the Treasury put off targeting oligarchs and officials close to Russian President Vladimir Putin, it said further sanctions were coming and for the first time blamed Moscow for cyber attacks stretching back at least two years that targeted the US power grid, including nuclear facilities.

After initially equivocating about a chemical attack on a former Russian double agent in Salisbury, England, the White House joined a statement by the leaders of Britain, France and Germany in which they said they "abhor the attack" and blamed it on Moscow.

Moscow has denied any involvement in the poisoning.

Thursday's actions have caused some Russia analysts to ask whether the administration is taking a more confrontational stance despite Mr Trump's repeated statements in the election campaign that he wanted a better relationship with Moscow, his praise for Mr Putin and apparent reluctance to criticise the Russian leader.

"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 Mr Putin showing a video on March 1 of a weapon appearing to hover over what looked like a map of Florida, home to Mr 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.

TRUMP EXASPERATED

While there was a sense at the White House that there has been a hardening of Mr Trump's view towards Russia, at least for now, it was unclear whether this represented a long-term shift.

A senior administration official said there was some feeling that the goodwill that Mr Trump extended towards Russia when he took over has not been reciprocated and that the Russians do not want to have good relations with the United States.

This has exasperated Mr Trump, who instructed his team to make sure the US appeared to be in solidarity with Britain over the nerve agent attack.

Mr Eugene Rumer, a former US national intelligence officer for Russia, suggested that Mr Trump's approach may ultimately be guided by Special Counsel Robert Mueller's investigation into whether Russia meddled in the election campaign.

The Kremlin denies interfering. Mr Mueller is also investigating any potential collusion between the Trump campaign and Moscow officials, something Mr Trump denies.

"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," Mr Rumer said.

Officials from multiple US agencies discussed next steps at a meeting on Thursday (March 15), with one aim being to avoid personally attacking Mr Putin and taking in-your-face steps that could prompt retaliation.

In announcing Thursday's sanctions, US officials made clear more would follow.

"This is just one of a series of ongoing actions that we're taking to counter Russian aggression," one US official told reporters. "There will be more to come, and we're going to continue to employ our resources to combat malicious Russian activity and respond to nefarious attacks."

Mr Sergei Skripal, 66, and his daughter Yulia, 33, were found unconscious on a bench outside a shopping centre on March 4 after being exposed to what the British authorities have identified as a military-grade, Soviet-era Novichok nerve agent.

Another US official attributed the sharper edge to US policy to increasingly brazen behaviour by Russia in cyberspace and on the ground, culminating in the Salisbury attack.

This US official, who spoke on condition of anonymity, also pointed to Russia's refusal to restrain Syrian President Bashar al-Assad and the role of Russian "mercenaries" in Syria, now entering its eighth year of civil war.

The official said it was unclear if Mr Trump himself saw Russia as an adversary but suggested Mr Putin may have "overplayed his hand" by leaving Russian fingerprints on the hacking, the chemical attack, the deployment of ground-launched cruise missiles which the US says violate an arms control treaty, and a March 1 speech on "invincible" Russian weaponry.

"If the president felt like Putin was one-upping him, not to mention stealing the limelight, then it wouldn't be surprising that he would react," the official said.

While more sanctions are expected, it was not clear if the Trump policy towards Russia was changing, especially given Mr Trump's unpredictability, said a third official, who is involved in talks on next steps.

"Tomorrow is another day," the official said.