But in the latest salvo in this battle, the president of the European Association of Archaeologists said on Friday that he had visited the 700-foot (213-meter) hill and saw no evidence that it was human-made.

Speaking at a press conference in Sarajevo, Anthony Harding told reporters the pyramid-shaped hill was a natural phenomenon.

"My opinion and the opinion of my colleagues is what we saw was entirely geological in nature," the AFP news agency quoted him as saying.

"Further work of the same kind would simply produce the same results. I don't think it would change any view about what the nature of the hill is," he said.

Harding, an archaeology professor at England's University of Exeter, visited Visoko, 18 miles (30 kilometers) from Sarajevo, on Thursday.

(See a map of Bosnia and Herzegovina.)

European Pyramid?

In April 2006 the Houston-based Osmanagic and a mostly volunteer crew began limited excavations in the area and drilled exploratory wells.

The team uncovered what they describe as large stone blocks shaped by human hands and a network of tunnels fronted by a wide, paved entranceway.

Osmanagic has speculated that Illyrians—ancient ancestors of today's Albanians—could have built the alleged pyramid perhaps as early as 12,000 years ago during the last ice age.