He urged the international community to address the “immense humanitarian tragedy” in both countries.

The Pope also called for peace in the Holy Land, Ukraine, Libya, Yemen, Nigeria, Sudan and the Democratic Republic of Congo.

And he once again referred to the persecution of Christians in many countries.

Addressing the faithful in a rain-drenched St Peter’s Square, the Pope said: “We ask Jesus, the victor over death, to lighten the sufferings of our many brothers and sisters who are persecuted for his name, and of all those who suffer injustice as a result of ongoing conflicts and violence.

“We ask for peace, above all, for Syria and Iraq, that the roar of arms may cease and that peaceful relations may be restored among the various groups which make up those beloved countries.

“May the international community not stand by before the immense humanitarian tragedy unfolding in these countries and the drama of the numerous refugees.”

He also said his thoughts and prayers were with the young people killed in last Thursday’s massacre at Garissa University College in Kenya.

Referring to the outline agreement on Iran’s nuclear programme recently reached in the Swiss city of Lausanne, he expressed hope that it might be “a definitive step toward a more secure and fraternal world”.

The Pope concluded his address by saying: “We ask for peace and freedom for the many men and women subject to old and new forms of enslavement on the part of criminal individuals and groups.

“Peace and liberty for the victims of drug dealers, who are often allied with the powers who ought to defend peace and harmony in the human family. And we ask peace for this world subjected to arms dealers.”

Two days ago, during a Good Friday service in Rome, the Pope condemned what he termed the “complicit silence” about the killing of Christians.

The service came a day after almost 150 people were killed in the attack on the Kenyan university by Islamist militants who are said to have singled out Christians as their victims.