The Pope has made a remarkable intervention in Russia's invasion of Ukraine.

Pope Francis visited the Russian embassy on the Via della Conciliazione in Rome on Friday morning to express his concerns about the war directly with country officials. 

Vatican press officer Matteo Bruni said he spent over half an hour at the embassy. 

At his General Audience on Wednesday, the Pope called on the faithful to join in a day of prayer and fasting for the war on Ash Wednesday, 2 March. 

He decried the invasion and called on "those with political responsibility to examine their consciences seriously before God, who is the God of peace and not of war". 

In a message posted to the Pope's Twitter in both English and Russian, he quoted his encyclical "on fraternity and social friendship" in which he condemned war as a "failure".

"Every war leaves our world worse than it was before," he said.

"War is a failure of politics and of humanity, a shameful capitulation, a stinging defeat before the forces of evil."

As fighting entered day three, Ukraine said 198 civilians, including three children, have been killed. 

Ukrainian women and children fleeing the fighting have been streaming into neighbouring Poland, but men between the ages of 18 and 60 are barred from leaving the country. 

Ukrainian President Volodymyr Zelensky has said the country will continue to defend itself.