Pope Francis is to meet with King Abdullah of Jordan on Thursday.
The meeting at the Vatican will be the first between the Jordanian king and Pope Francis.
King Abdullah met Pope Emeritus Benedict XVI in Amman during his 2009 apostolic journey to the Holy Land.
It is expected that the Syrian conflict will feature in the meeting between the king and Pope Francis.
The Pope expressed grave concern about the situation during his Angelus address to the faithful in St Peter's Square on Sunday.
He appealed to the international community to help restore peace to the country.
"The growth in violence in a war between brothers, with a multiplication of massacres and atrocities that we have all been able to see in the terrible images of recent days, moves me once again to call in a loud voice for the fighting to cease," he said.
"It is not conflict that offers a perspectives of hope for resolving problems, but it is the capacity for meeting and dialogue."
He added: "I appeal to the international community to show itself to be more responsive to this tragic situation and to do all it can to help the beloved Syrian nation find a solution to a war that sows destruction and death."
Tensions have heightened in recent days as the US, UK and other countries consider a military response to evidence of a gas attack on civilians in the Ghouta suburb of Damascus that killed nearly 1,300 people. A military strike is opposed by Russia.
UK Prime Minister David Cameron said the use of chemical weapons was "morally indefensible".