Five companies filed bids for upgrading the army's 20 Soviet-built MiG-29 fighters in an international tender aimed at bringing Bulgaria’s air force up to NATO standards. The five offers, opened at the defence ministry came from Russia's RSK MiG, Israel's Elbit Systems, European aerospace company EADS, IAI (Israel Aircraft Industries) and Belarus' 558th auto repair plant Baranovichi. Under the terms of the tender, called in mid-December, the bidders are required to repair the planes at Bulgaria's aviation repair plant Georgi Benkovski. No details of the bids were made public. No deadline for selecting a winner was set but a defence ministry official told Reuters a decision could be expected in February.