Bulgaria's defence ministry said that it has invited state-owned company Terem Holding to submit a bid for a framework contract for an overhaul of 13 Russian-made T-72 battle tanks, with an estimated value of 6.67 million levs ($4 million/3.4 million euro). Terem Holding was also invited to table a proposal for a 1.5 million levs contract for repair of 60 rangefinders for the T-72s, the ministry said on Wednesday. The ministry also invited Belarus' state-owned company Belspetsvneshtechnika to bid for the rangefinders repair contract. The tank overhaul contract envisages repair of two tanks in 2018, four in 2019 and 2020 each, and three in 2021.The rangefinders should be repaired in batches of 12 over a five-year period. The main activities of Terem, which was established in 1963, include overhaul, medium repair and manufacturing of military equipment.