The head of the Tohoku Paleolithic Institute apologized Monday to officials of the town of Tsukidate, Miyagi Prefecture, after one of the institute's senior researchers admitted planting artifacts at an archaeological site located in the town.

Toshiaki Kamata explained the series of events leading up to Sunday's admission by Senior Director Shinichi Fujimura, 50, that he fabricated the discovery of stoneware at the Kamitakamori ruins -- initially thought to be more than 600,000 years old -- by burying the artifacts himself.

Fujimura, who said he was compelled to fabricate findings as he felt pressure to make a discovery to put him in the history books, was formally expelled from the institute, Kamata said Monday.

"While they were the actions of an individual, we feel responsible as an organization," Kamata said tearfully to Deputy Mayor Kiyohiko Sato.