Afghanistan's ruling Taleban paraded a haul of documents and material in front of the country's Supreme Court Thursday. They say the articles conclusively prove eight Western detainees tried to spread Christianity, an offence that violates strict Taleban laws.

Lawyers for the Taleban said the seized computer discs, audio tapes and Bibles translated into local Pashto and Dari (Persian) languages prove two Americans, two Australians and four Germans -- all members of the German-based group Shelter Now International -- tried to convert Afghans.

"Their priority was to propagate Christianity which they were not supposed to do here," Sayed Rehmatullah Hashmi, an aide to the Taleban's foreign minister, told reporters.

Hashmi said materials were seized from the office of International Assistance Mission (IAM), a Christian relief and development agency which has since been ordered out of the country.

He showed reporters a copy of IAM's constitution, which he said is particularly damning.

The document read: "The purpose of the IAM is to minister to the needs of the people of Afghanistan in the Name and Spirit of Jesus Christ and to make Him known to them by work and life."

The third article of the constitution read: "It is also the purpose of the IAM to help in strengthening the Christian Church in Afghanistan and throughout the world."

Hashmi said the document shows that the group was well aware it was illegal to preach Christianity in strictly Islamic Afghanistan.

A copy of a document called "Publishing Guidelines" warned aid workers and church leaders to remain cautious about whom they spoke to regarding Christianity.

"Prayer partners and friends should know where your IAM team member is but the general public need not know that as a mission organisation you are working in the Islamic State of Afghanistan," the document read.

Afghans who try to convert others to Christianity face the death penalty. However, the punishment for foreigners is unclear. The Taleban's leader Mullah Mohammad Omar will decide on the punishment in this case.

Taleban chief justice Mawlawi Noor Mohammad Saqib told the Afghan Islamic Press, based in Pakistan, that if the eight are found guilty, they would be punished according to Islamic law.

"We will punish them according to the laws they have broken," he said. "If they have broken the law and should be hanged, then we will punish them like that."

Earlier Thursday, Wakil Ahmed Muttawakil, the Taleban Foreign Minister, denied a report that he had received a proposal to swap the detainees for a militant Muslim cleric, jailed in the U.S. Sheikh Omar Abdel-Rahman is serving a life sentence for bombing the World Trade Centre in New York.

Muttawakil said family members of the detainees would be allowed into the country to attend the trial.

Parents of the two Americans were allowed to visit with their daughters Thursday and reported them to be in good health. The U.S. has asked that a Red Cross doctor be allowed to access the detainees to deal with general health issues.

Wednesday, the U.S. ambassador to Pakistan and the German and Australian charges d'affaires asked for legal representation and interpreters for the trial. The Taleban has yet to send a reply. The three delegates met a Taleban representative Thursday, but said they were unable to learn anything new about the case.