Bishops Matthew Audu of Lafia and George Dodo of Zaria urged officials to boost intelligence gathering efforts and muster the political will to find the girls, who were taken from their dormitories by Boko Haram forces during a middle-of-the-night raid at a school in Chibok in northeastern Nigeria April 14, 2014.
The bishops told Catholic News Service it is unlikely that all of the girls will be found because media have reported that some had been killed or sold off to be married by the insurgents. They urged the country to pray for the abductors so that they have a change of heart and consider releasing the students.
New video images recently obtained by CNN and apparently filmed on Christmas Day showed some of the girls dressed in black robes pleading with the Nigerian government to cooperate with the militants on their release. They said they were being treated well but wanted to be with their families.
Family members and friends identified some of the young people as students from the school.
The Catholic News Agency for Africa reported that relatives of the girls marched in the capital, Abuja, on the anniversary, calling for government action.
"Only God knows what their abductors might have done to them, where they would be by now. It might be true that some might have been killed, some molested and some married out by their abductors," Bishop Audu said. "That we can still recover all those abducted on ... is not certain," Bishop Audu said.
"That they are still within the custody of their abductors after two years does no credibility to the corporate image of Nigeria as a nation," he added.
Bishop Audu, whose diocese is in central Nigeria, called for a concerted effort from by world leaders, starting from Nigeria's neighbors in West Africa, to fight terrorism by contributing forces and weapons to a multinational joint task force assembled to root out the insurgents.
"World leaders must find ways to block the sources of funding of the insurgents and those supplying them those arms and ammunition which they use to attack legitimate governments and innocent people," he said.
Bishop Dodo, whose diocese is in northern Nigeria, said that he was praying that missing girls would be discovered. "I am not sure that we will be able to rescue all of them after two years of their abduction. ... If it we are fortunate, we may get some of them back but not 100 percent," he said.
He also expressed concern for thousands of other internally displaced persons living in various refugee camps who cannot return to their homes.
"The federal government must also look into the plights of other Nigerian workers being owed several months of unpaid salaries by their state governments," he said.
"Many do not have money to report for duties at their offices, the federal government should bail out the state governments with financial assistance for them to fulfill their obligations to their workers and citizens.''