Mechthild Flury-Lemberg, speaking by phone from Bern, Switzerland, acknowledged the tests, but would not explain what she was studying or what the tests consisted of.

She said the Vatican ( news - web sites) was aware of the tests. A Church spokesman was not available to confirm this, and a priest at the Turin cathedral where the shroud is kept refused to comment.

Flury-Lemberg said there would be a news conference on the matter in about two weeks or at the latest by early September.

"We have an agreement with Turin that we will only give information to the press when we have the possibility to give you real photographs and things like that," Flury-Lemberg said Friday.

The shroud, which remained in the Turin cathedral, is a strip of linen four meters (13 feet) long and one-meter (three-feet) wide that is marked by an image of Jesus, which believers say was left by his body after he was taken off the cross.

A carbon-dating test ended in 1988 with a scientific team declaring that the shroud apparently came from medieval times. Disputes have flourished since then on the validity of that study and others, including one by researchers at The Hebrew University that concluded that pollen and plant images on the shroud showed it originated in the area around Jerusalem sometime before the eighth century.

Typically, the shroud is kept under tight security, with only a handful of people allowed access, among them is Flury-Lemberg, who was part of a commission established to study its conservation in 2000, said shroud expert Luigi Gonella.

The shroud has been shown to the public for limited periods, and during 2000 more than 1 million visitors viewed it during a special showing for Holy Year celebrations.

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