The few Christians remaining in war-torn Yemen gather for liturgies and prayer meetings in the basement of a villa in the city of Sanaa where they remain "invisible" in order to stay safe, Bishop Paul Hinder has told Vatican Radio. Bishop Hinder, the apostolic vicar of southern Arabia, said that it is not specifically Christians who are at risk in the conflict, but foreigners who have been told to leave the country. All of the country's Catholics are foreigners, mostly foreign workers from India, he said. As more civilians are killed in the crossfire of fighting between the government and armed rebel forces, even humanitarian organisations have called on their aid workers to leave the area for their own safety. The United Nations has called for at least a temporary ceasefire to give foreigners a chance to leave, but Bishop Hinder said he is not convinced the warring sides will agree. "We have celebrated only a few days back the mystery of the death and resurrection of our Lord," he said, "and I think in that message itself is the encouragement for the Christians that we should never give up." "There is someone stronger than every political power, and that is the strength of the risen Lord," Bishop Hinder said he told the Christians of Yemen. "I can only tell them you are not alone, there are many, many in the whole world who are caring for you, but of course our means are limited except the incredible means we have in the prayer and in the solidarity of our faith."