KADUNA, NIGERIA — Kidnappers are demanding a ransom of 60 million naira (about $200,000) for a German archaeologist and his associate abducted this week from a northern Nigerian village, a worker at the excavation site said. The worker said he heard a man make the demand in a telephone call Thursday to the site’s supervisor. The caller warned not to involve police or security forces, said the worker, who spoke on condition of anonymity because he is not authorized to speak to reporters. Police special forces and a special investigative team for kidnappings were searching around Jenjela village in Kaduna state, where gunmen Wednesday abducted professor Peter Breunig and his associate Johannes Behringer and walked with them into the bush. Nigeria’s acting President Yemi Osinbajo summoned the federal police chief for a briefing Thursday on efforts to find the kidnap victims, the official News Agency of Nigeria reported. The report also said two villagers accompanying the Germans were shot and killed in the kidnapping. Police could not immediately be reached Friday to confirm that. Kidnappings for ransom are common in Nigeria, but victims usually are freed unharmed after a ransom is paid. Breunig, 65, and Behringer, who is in his 20s, are part of a four-person team from Frankfurt’s Goethe University collaborating with the Nigeria’s National Commission for Museum and Monuments to recover relics of the Nok culture. The early Iron Age people are considered the earliest ancient civilization of the region that is now Nigeria, famous for their terracotta sculptures. *VOA