MAIDUGURI, Nigeria — Witnesses say Islamic extremists in northeast Nigeria are lining up elderly people and shooting them — a new tactic instilling fear in areas the militants call an Islamic caliphate.

Residents from five villages say people too elderly to flee Gwoza local government area are being rounded up and taken to two schools where the militants open fire on them. The villages are about 130 kilometers (80 miles) southeast of Maiduguri, the Borno state capital.

The reports were confirmed Friday by Muhammed Gava, a civil defense group spokesman. He said more than 50 elderly people have been killed at Government Day Secondary School and an unknown number at Uvaghe Central Primary school.

Government officials did not immediately comment on the reports.

Extremists have killed thousands of people in a 5-year uprising.