Nine layers of millenia-old ruins dating back to the ancient Hittite civilization were discovered in central Turkey, an archeologist said on Thursday. 'We have identified nine layers of construction belonging to the Hittite period,' Kimiyoshi Matsumura told Anadolu Agency in Kırıkkale, where the dig site is located. Matsumura said he and his team unearthed a city wall dating back to 600-700 B.C., adding that the team had found a layer underneath dating back to 14th century B.C. The excavation area covers a huge city, Matsumura said adding that the team would continue work even if it took more than 100 years to unearth the entire area. Matsumura said the archeologists discovered clay tablets dating back to the Hittites that are suspected of being diplomatic letters between two countries. 'It was also written in this letter that a messenger was sent who did not return,' Matsumura added. Matsumura said they had also discovered a bone seal belonging to the Hittite capital of Boğazköy (Hattusha) currently located in Turkey's central Çorum province, further evidence that the city was related to the Hittites.