POPE Francis has rejected Russia’s use of the term “special military operation”, instead calling it a “war which sows death, destruction and misery”.

He urged an immediate end to the fighting during his weekly address to crowds gathered in the Vatican, adding “in Ukraine, rivers of blood and tears are flowing”.

The Pope said: “In that martyred country the need for humanitarian assistance is growing by the hour. War is madness, please stop."

Many more people than usual gathered in front of St. Peter's Basilica for the pope's Sunday appearance, some holding multi-coloured peace flags as well as the blue and yellow flag of Ukraine.

Pope Francis said he has dispatched two cardinals to Ukraine, a highly unusual move.

The pontiff said on Sunday “the Holy See is willing to do everything to put itself in service for peace.”

The papal almsgiver, Cardinal Konrad Krajewski, has been dispatched with aid, along with Cardinal Michael Czerny, who is head of the papal office dealing with migration, charity, justice and peace.

Andriy Yurash, Ukraine's ambassador to the Vatican, told Reuters he was "very, very happy" that Pope Francis had called the conflict a war.

He said: "Even if the pope did not say the word 'Russia', everyone in the world knows who the aggressor that invaded us is and who started this unprovoked war.”