Lt. Muath Kasasbeh, 26, became the first soldier serving with the U.S.-led coalition battling Islamic State to be held by the militants after his plane went down on Christmas Eve in northeastern Syria.

"Since that time, our church bells have rung, and prayers have been uttered urging for the freedom for our brother hero, and for his safe return," Patriarch Twal told Kasasbeh's father, Safi, Jan. 3, the commemoration of the birthday of Islam's Prophet Muhammad.

"Despite the wrenching agony caused by his capture, Muath has brought Jordanians together and made them feel the taste of national unity," said the Jordanian-born patriarch.

Jordan's King Abdullah II and ordinary Jordanians have travelled to this southern impoverished village to show their solidarity with the Kasasbeh family, which has pleaded with Islamic State militants to treat him well.

"My message to them on the occasion of the birth anniversary of Prophet Muhammad is to treat my son well and consider him a guest. I hope that he will be released soon," said Safi Kasasbeh.

Jawdat Kasasbeh told Catholic News Service that serious negotiations are taking place for his brother Muath's release. However, he cautioned that one of the key demands is for Jordan to leave the international coalition fighting Islamic State. Jordan has reaffirmed its commitment to fighting terrorism, but some citizens have expressed their unhappiness over the kingdom's public involvement in the military coalition.

Jordan has threatened Islamic State with "grave consequences" if the pilot is harmed. Meanwhile, it has halted its combat missions as part of the international coalition over Syrian territory.

Several Islamic State-affiliated Twitter accounts have asked followers to suggest ways of killing Muath Kasasbeh.

Unconfirmed reports said U.S. Special Forces made two hostage rescue attempts Jan. 1. The Jordanian was reportedly one of several captives who would have been saved had the rescue mission not been abandoned in Syria.

Fr. Rifat Bader of the Catholic Center for Studies and Media in the Jordanian capital, Amman, said prayers during the Christmas and New Year's holidays focused on Muath Kasasbeh's safety and return home as well as for officials to be granted wisdom and patience to resolve the incident and avoid escalation.

The delegation accompanying Patriarch Twal included representatives from the Latin Patriarchate, which includes Jordan; various Orthodox denominations; the apostolic nunciature in Amman; Chaldean Catholics; and the Lutheran Church.