The Vatican’s chief diplomat, Cardinal Pietro Parolin is seeking to defuse tension over comments made by the Pope that Ukraine should "show the courage of the white flag" and open talks with Russia to end the two-year-old war.

It follows the summoning on Monday of the papal nuncio to Ukraine by the country’s foreign ministry which had expressed "disappointment" over the Pontiff’s remarks. 

Cardinal Parolin, the Vatican's secretary of state, has now made it clear that the first condition for any negotiations to end the war in Ukraine is that Russia should halt its aggression. Speaking to an Italian newspaper, Corriere della Sera, the Pope’s second in command said the Vatican was pressing for a ceasefire and that the aggressors should stop firing first.

Making clear that he considered Russia the aggressor, Parolin said "the war unleashed against Ukraine was not the effect of a natural disaster," but of human choices.

"The same human will that caused this tragedy also has the possibility and the responsibility to take steps to end it and to open the way to a diplomatic solution."

Cardinal Parolin made similar comments to Italy's state-run RAI, saying: "Peace in Ukraine will have to be a just peace.

"It means recognising mutual rights and also mutual duties, above all, taking into account the dignity of people."

Pope Francis’ comments were part of an interview recorded last month with a Swiss broadcaster, but they were only made public at the weekend. 

They triggered very different reactions from NATO and Moscow.

The Kremlin said the pope's call to end the war was "quite understandable", but the boss of the Western military alliance said now was not the time to talk about "surrender."

Attempting to defuse the situation and clarify Francis' remarks, Parolin said the pontiff wanted "to create the conditions for a diplomatic solution in the search for a fair and lasting peace."

To do this, Parolin said it was "obvious" that both sides must come to the negotiating table and the first condition must be "putting an end to the aggression."

(Additional reporting by Reuters)