Two people have been arrested after protesters dyed the Trafalgar Square fountains in central London red.
The Animal Rebellion group, which says animal farming is risking future pandemics, warned government ministers have “blood on their hands”.
While some activists waded fountain’s waters, others held placards and staged a socially distanced protest in Trafalgar Square.
The Metropolitan Police said two people had been arrested on suspicion of criminal damage and taken into custody.
The protesters said they wanted to raise attention to animal exploitation which they say caused the coronavirus pandemic.
“We are here today to demand that the government prevent future pandemics by ending animal farming and transitioning to a plant-based food system,” the group tweeted.
It added the government must “protect the people, not support climate-destructive and exploitative industries”.
Stephanie Zupan, of Animal Rebellion said: “The government must begin a transition towards a plant-based food system or risk future zoonotic pandemics of catastrophic proportions.”
Scientists believe Covid-19 developed at a market in China where species that don’t mix in the wild were kept and slaughtered in close confinement.
The group said protests were also held in other cities, including Bristol, Brighton, Amsterdam, Barcelona and New York.
Animal Rebellion, which promotes mass civil disobedience in full public view, is also calling on the government to acknowledge that three out of every four new infectious diseases originate from animals, as stated by the US Centres for Disease Control and Prevention.
“The warnings from Covid-19 could not be starker,” said Ms Zupan.
Another protester, Kieran Blyth, added: “The government are playing with the potential of tens of thousands more deaths.”
Members pointed to the Agriculture Bill going through the House of Lords, which could lead to imports of meat from lower-welfare animals.
A government spokesperson said: “Every livestock farm in England, regardless of scale, must comply with our comprehensive animal-welfare legislation.
“We take potential breaches of animal-welfare legislation very seriously, and where welfare regulations are breached, appropriate action is taken.”
