Downing Street has rowed back after saying sweeping sanctions were designed to "bring down the Putin regime".
No10 said Prime Minister Boris Johnson's official spokesman "mis-spoke" when he made the remark in a media briefing today.
The spokesman insisted Britain was not seeking "regime change" in Moscow, where Vladimir Putin runs a nuclear-armed nation.
The gaffe came as Ukraine and its allies called for a United Nations inquiry into possible war crimes committed by Russia.
A Ukrainian draft resolution will be considered on Thursday, a week after Russia launched a full-scale invasion of the country.
Ukraine's health ministry said yesterday that a least 352 civilians, including 14 children, had been killed since the invasion began.
People fleeing Ukraine have poured into central Europe, with queues at border crossings after the invasion pushed nearly 400,000 people to seek safety abroad.
The UK Prime Minister's official spokesman made the comments in a regular briefing for journalists when asked about City law firms who still work for Russian firms.
He said: "The Prime Minister's view is that Putin's regime, and Putin, must be treated like a pariah state - and that businesses should think very carefully if they are still continuing to do anything that props up the Putin regime.
"The United Kingdom, the Prime Minister, is very clear that we do not want to unnecessarily inflict damage on the Russian people, many of whom are bravely taking to the streets to protest this violence, this invasion.
"But the measures we are introducing, that large parts of the world are introducing, are to bring down the Putin regime.
“And we think anyone who is actively seeking to support any elements of the Putin regime should think very carefully about the actions they’re taking.”
Pressed to clarify whether the measures are “intended to bring down the Putin regime”, he said: "Yes, so the sanctions we've introduced, the widespread sanctions, aim to inflict financial pain on Putin and his regime, to stymie the Russia war machine as it attempts to subjugate a democratic European country."
But the spokesman then clarified during the same briefing that “we’re not seeking anything in terms of regime change”.
Asked “you want to bring down the Putin regime, you want to see Putin out of power?”, the spokesman replied: “We’re not seeking anything in terms of regime change.
"What we’re taking about here, clearly, is how we stop Russia seeking to subjugate a democratic country. That’s been the message throughout.
"This is simply about preventing an unwarranted attack on a democratic country.”
No10 then later said the Prime Minister's official spokesman "misspoke" when he said Western sanctions "are to bring down the Putin regime".
The spokesman went on to say: "We're not seeking anything in terms of regime change. What we're talking about here clearly is how we stop Russia seeking to subjugate a democratic country."
Boris Johnson will fly out to Poland and Estonia for crisis talks over the escalating conflict in Ukraine.
Downing Street confirmed the Prime Minister would visit the region on Tuesday for meetings with allies and NATO Secretary-General Jens Stoltenberg.
The Russian offensive in Ukraine has entered its fifth day, with Vladimir Putin's forces targeting the capital Kyiv and major cities of Kharkiv and Chernihiv.
Defence Secretary Ben Wallace warned the invasion was likely to become "more violent" as Russia resorts to more brutal tactics to advance.
He said the Russian handbook pointed to "ruthless, indiscriminate bombing of cities" with "high casualty levels" as Moscow's troops meet stubborn resistance.
British Government insiders believe Mr Putin expected to sweep through the country and Russian forces have been caught off guard by the level of opposition from Ukrainian people.
They believe President Putin has become increasingly isolated, with aides possibly too afraid to deliver bad news as his behaviour becomes more irrational.
Boris Johnson opened Cabinet by saying Vladimir Putin had made a "colossal mistake" believing his troops would be "garlanded with roses" by Ukrainians.
And No10 accused Putin of a “distraction technique” after he tried to blame Liz Truss for his own threat about using nuclear weapons.
Downing Street slapped down the Kremlin for saying the President put Russia ’s nuclear deterrent on a “special regime of combat duty" after statements from the UK Foreign Secretary.
According to the Interfax news agency, Kremlin spokesman Dmitry Peskov told a press briefing: "I would not call the authors of these statements by name, although it was the British foreign minister."
It was not immediately clear which statements by Ms Truss the Kremlin was referring to.
Yesterday she warned the conflict could escalate into a clash between Russia and NATO allies.
She told Sky News: “We are not just fighting for the people of Ukraine and the sovereignty and self-determination of Ukraine.
“This long-running conflict is about freedom and democracy in Europe because if we don’t stop Putin in Ukraine, we are going to see others under threat – the Baltics, Poland, Moldova and it could end up in a conflict with NATO.”