Christian Solidarity International (CSI) also appealed to the United Nations High Commissioner for Human Rights, Mary Robinson, to look into a mass trial that began in the Sudanese capital in October.
In its letter, made available at the UN European headquarters in Geneva, CSI said its appeal related "to a threat of crucifixion that would horrify Christians worldwide and the international community".
The Washington Post reported yesterday that the Reverend Hillary Boma and another priest were on trial for detonating almost a dozen bombs around Khartoum on June 30 in an alleged plot to mar official celebrations of the ninth anniversary of the coup in Sudan. Father Boma, 57, is identified as the chancellor of the archdiocese of Khartoum.
Sudan has blamed the bombings on the opposition alliance fighting the government for more independence in the mostly Christian south.
Khartoum's treatment of Christians came under the spotlight a year ago when the US imposed sanctions on Sudan for denial of religious freedom. Sudan rejects the charge.Reuse content