LONDON: British Prime Minister Boris Johnson said on Friday that Russian forces must immediately cease an attack on a Ukrainian nuclear power plant where a fire broke out.

Johnson spoke to Ukrainian President Volodymyr Zelenskiy about the situation at the Zaporizhzhia nuclear power plant in the country's southeast.

"The prime minister said the reckless actions of President Putin could now directly threaten the safety of all of Europe," Downing Street said.

"He said the UK would do everything it could to ensure the situation did not deteriorate further," it added. "Both leaders agreed a ceasefire was crucial."