An environmental group on Wednesday called for a halt to baptisms in the Jordan River where tradition holds that Jesus was baptised, saying the waters there were dangerously polluted.
"Friends of the Earth Middle East call on regional authorities to halt baptism in the lower Jordan River until water quality standards for tourism activities there are met," said a statement from the group.
The group issued the call following media reports that Israel's health ministry had urged the tourism ministry to stop people bathing in the river, saying it posed a health risk.
In recent years the flow of the river has slowed to a dirty trickle as fresh water running into the river has been replaced with sewage.
"Sadly, the lower Jordan River has long suffered from severe mismanagement with the diversion of 98 percent of its fresh water by Israel, Syria and Jordan and the discharge of untreated sewage, agricultural run-off, saline water and fish pond effluent in its place," the statement said.
The ministry could not immediately be reached for comment.
The Israeli site, known as Qasr al-Yehud, is a closed military area near the West Bank city of Jericho. In recent years the army, under pressure from the tourism ministry, has opened it to pilgrims on special occasions.
Nearby, on the east bank of the river in Jordan, is Wadi Kharrar. It was found by archaeologists in 1996, and the Jordanians say it is the biblical "Bethany Beyond the Jordan" where John the Baptist exercised his ministry.
Excavations there began in 1997 after the redeployment of Jordanian troops who had controlled it when it was a mine-infested no-go zone until a 1994 peace treaty with Israel.
Jordan and Israel each claim that the true baptismal site is on their territory, competing to build hotels and facilities to attract tourists and pilgrims.
Jesus is believed to have entered the waters some 2,000 years ago to be baptised by John, who immersed his followers in the Jordan to symbolise their purification in the eyes of God.