DENVER (AP) — Chesapeake Energy Corp. has been fined $2.1 million for under reporting natural gas produced on Indian leases in Oklahoma.

The Department of Interior's Office of Natural Resources Revenue Office in Denver said Monday it issued the civil penalty against the Oklahoma City-based company for failing to comply with an October 2011 order requiring it to review the amounts reported for more than 100 leases. In a statement, the office said that Chesapeake said it complied with the order in 2012 but follow up testing found additional under reported volumes which were then corrected in 2013.

The 2011 order covered land owned by tribes and individual Native Americans. The fine covers misreported amounts produced on the individual leases only.