The Russian Air Force has added two dozen upgraded multi-role MiG-31BM fighters to its fleet and more than 100 others are expected in coming years.

The first 24 aircraft, which NATO calls the Foxhound, were modernized by the Rostec Corporation, which is inducting about a dozen earlier variants of the MiG-31 for upgrade each year.

"After completing the modernization of the MiG-31, we expect that military forces will have more than 130 updated, outstanding aircraft with key technical parameters available for use," Deputy Defense Minister Yuri Borisov said.

The MiG-31 interceptor, first produced in 1979, is based on the MiG-25, which it replaced. It is a two-seat, long-range fighter for interception and destruction of cruise missiles, low-flying satellites and other aerial targets. It has a maximum speed of 1,860 miles per hour at high altitude and about 960 mph at low altitude.

Its combat radius, depending on speed, varies between about 440 miles and 900 miles.

Rosstec said the new BM variant, which can engage ground targets, features new avionics. Its Zaslon-M weapons control and radar system, developed by V. Tikhomirov Scientific Research Institute of Instrument Design, provides increased target detection range -- nearly 199 miles -- and a firing range of about 174 miles.

The onboard radar system of the MiG-31BM can simultaneously track up to ten air targets, Rostec said.