The Greek government on Wednesday gave the go-ahead for the country's military to open talks on buying some 420 armored vehicles from Russia, an official said. A Defense Ministry official said senior Cabinet officials approved the start of "substantive negotiations" on the purchase, which would include talks on possible joint production of the medium-sized tanks. The official could not say how much the deal would be worth. He was speaking on customary condition of anonymity. State NET television said some $1.8 billion had been budgeted for the military vehicles.