In Bethlehem, Catholic churches were preparing special prayers for the 84-year-old pontiff, whose condition was described by the Vatican as "very serious".
"We are following the news all the time," said Saadi Abu Saada, a 28-year-old journalist, lines of worry etched across his face.
Many people in Bethlehem, the traditional birthplace of Jesus Christ, and in Jerusalem's Old City were glued to their televisions and radios, refusing to believe the Pope was close to death.
"Until now, we have no news about the Pope but we know he is in critical condition," Roman Catholic priest Father Shawki said at the Latin patriarchate in the Old City.
The Roman Catholic community numbers about 400,000 in Israel, Palestine and Jordan. The Pope visited the region in 2000.
Prayers in Iraq
In Baghdad, Iraqi priests at Catholic churches conducted prayers for the ailing Pope, who opposed the US-led invasion of their country and made multiple calls for peace.
Iraqi Christians recognized the Pope
as one who wanted peace
Father Andraos Abuna of the Chaldean St Mary church in the capital's central Mansur district said prayers for the pontiff in the morning and was due to hold a special service on Saturday.
Abuna recalled that "men of religion want a peaceful solution in the region" and that the pontiff had sent a cardinal to Iraq in the 1990s to try to encourage deposed leader Saddam Hussein to make peace with Israel.
Pios Qasha, priest for Baghdad's St Joseph's parish, said that "the pope is a man of peace," and that under his papacy "the Vatican called on both sides in the (1980-1988) Iran-Iraq war to put down their weapons."
Christians make up about 3% of the Iraqi population of 27 million, although the community has dwindled because of emigration in recent decades.
All of the country's main denominations - Assyrian, Syrian, Armenian and Greek - have Catholic wings. The Chaldeans are Assyrians who recognise the authority of the Holy See.
Originally concentrated in northern Iraq, the estimated 750,000 Chaldeans also now have large congregations in the capital and the main southern city of Basra.