US Secretary of State Antony Blinken has denied that the United States has any plans to bring about regime change in Russia or anywhere else.

Mr Blinken's comments come a day after President Joe Biden said his Russian counterpart, Vladimir Putin, should not be allowed to remain in power.

Mr Biden made the unscripted remark at the end of a speech in Poland.

Mr Blinken said the president simply made the point that Mr Putin could not be allowed to wage war against Ukraine.

The Kremlin dismissed Mr Biden's remark, saying it was for Russians to choose their leader.

"I think the president, the White House, made the point last night that, quite simply, President Putin cannot be empowered to wage war or engage in aggression against Ukraine or anyone else," Mr Blinken said on Sunday during a visit to Israel.

"As you know, and as you have heard us say repeatedly, we do not have a strategy of regime change in Russia, or anywhere else, for that matter.

"In this case, as in any case, it's up to the people of the country in question, it's up to the Russian people," he added.

"For God's sake, this man cannot remain in power," US President Joe Biden said about his Russian counterpart President Vladimir Putin during a speech in Poland's capital, Warsaw, on Saturday.

This was quickly followed by the White House saying Mr Biden wasn't calling for regime change, but was instead making a point about Mr Putin not being allowed to exercise power over his neighbours.

This was clearly an attempt at rolling back - the concern is that this is going to put more pressure on Putin and make him more uneasy.

Given that he is the head of a country that is struggling militarily, and is in control of a nuclear arsenal, the concern on the Americans' part is that they don't want to back Mr Putin into a corner.

Calling out for regime change directly could cause instability and increase unpredictability.

And the last thing you want in these circumstances is unpredictability.

Mr Biden's comment prompted strong criticism from veteran US diplomat Richard Haass.

The comments "made a difficult situation more difficult and a dangerous situation more dangerous", tweeted Mr Haass, who is president of the US Council on Foreign Relations.

"That is obvious," he added. "Less obvious is how to undo the damage, but I suggest his chief aides reach their counterparts & make clear the US is prepared to deal with this Russian government."

Mr Haass returned to the subject after the White House qualified President Biden's remarks, saying: "The White House walk back of @POTUS regime change call is unlikely to wash.

"Putin will see it as confirmation of what he's believed all along. Bad lapse in discipline that runs risk of extending the scope and duration of the war."

In Ukraine itself, the western city of Lviv, which had been spared the worst of the fighting, came under heavy rocket fire on Saturday. It was one of several targets in the west to be struck, despite Russia saying it would focus on the east.

In an impassioned, late-night video address, President Volodymyr Zelensky urged Western countries to supply planes, tanks, and missile defence systems to Ukraine. He said his country could not defeat Russian aircraft with machine guns.

Further south, Ukraine's top human rights official has said the only major city taken by Russian forces, the port of Kherson, is on the verge of a humanitarian catastrophe. Lyudmilla Denisova told the BBC that areas around the city were suffering shortages of food, water and medicine.

And the leader of the self-proclaimed Luhansk People's Republic in eastern Ukraine, Leonid Pasechnik, said there was likely to be a referendum on joining Russia "in the nearest future", according to Russia's state-owned news agency RIA.

On 21 February, Russia formally recognised the Luhansk and Donetsk breakaway republics as independent entities, paving the way for its invasion of Ukraine three days later.