Britain has sanctioned a Russian general who is believed to have ordered the attack on a theatre in the Ukrainian city of Mariupol, where 300 mainly women and children died despite warning signs on the building that civilians were sheltering.
Gen Mikhail Mizintsev is among 14 new individuals or organisations to be sanctioned by the UK on Thursday.
They include a well-known television presenter and two Kremlin-funded media operations accused of spreading "lies and deceit" about the invasion of Ukraine.
The 14 latest sanctions follow several previous rounds of penalties against more than 1,200 Russian and Belarusian individuals and entities in response to Russia's military operations against Ukraine.
"Britain has helped lead the world in exposing Kremlin disinformation, and this latest batch of sanctions hits the shameless propagandists who push out [Vladimir] Putin's fake news and narratives," UK Foreign Secretary Liz Truss said.
"We will keep on going with more sanctions to ramp up the pressure on Russia and ensure Putin loses in Ukraine. Nothing and no one is off the table."
Prime Minister Boris Johnson's official spokesman said the UK will continue to pursue more sanctions.
"Countries can adapt to sanctions over time so it's right that we continue to move forward on this," he said.
"It is equally right to impose sanctions on those who are seeking to disinform people at a mass scale."
London has targeted Col-Gen Mizintsev, head of the Russian National Defence Control Centre, who the UK foreign ministry said was responsible for the "Mariupol" assault over Russia's actions in the besieged Ukrainian city.
He has been linked to the planning and execution of the bombardment of Mariupol, among other key Russian military operations against Ukraine.
He was also heavily implicated in Russia’s military activity in Syria, including the destruction of the city of Aleppo.
Mr Johnson's spokesman said "on the face of it there does appear to be evidence of war crimes" in Mariupol.
TV-Novosti, which owns the global television channel RT – formerly Russia Today – was also sanctioned, as was Rossiya Segodnya, which controls the news agency Sputnik.
The UK broadcasting regulator Ofcom this month revoked RT's licence with immediate effect, saying it was not "fit and proper" to broadcast in the country.
In reaction, Margarita Simonyan, editor-in-chief of RT told RIA Novosti state news agency, that she would "add this insult to the total count".
Television presenter Sergey Brilyov, known for his interviews with high-profile political figures, has been sanctioned with the UK describing him as a "propagandist for Putin".
"Having previously lived in the UK, [he] will no longer be able to access any of his UK assets or continue business dealings," the ministry said.
Alexander Zharov, chief executive officer of Gazprom-Media, Alexei Nikolov, the managing director of RT, and Anton Anisimov, head of Sputnik International Broadcasting, were also targeted.
"These sanctions will ensure RT will not be able to find its way back on UK televisions, and will prevent companies and individuals operating in the UK from doing business with Russian state propaganda vehicles," the foreign ministry said.
Britain said it had also fast-tracked sanctions against another seven individuals connected to the Strategic Culture Foundation, which it described as an online journal registered in Russia.
The Foundation has recently been sanctioned by Australia for its role in spreading disinformation.
"The UK is operating closely with allies to target Russia's oligarchs, banks and businesses," it said.
The UK government has designated more than 1,200 individuals and organisations close to Mr Putin – including 76 oligarchs and 16 banks with a global net worth of £150 billion ($197.04bn) and £500bn respectively.