CHISINAU, Feb 14 (Reuters) - Moldova briefly closed its air space on Tuesday to investigate reports of a balloon-like object in the sky, a day after the small east European country accused Russia of plotting to bring down its government. Moldova's civil aviation authority said it acted after receiving a defence ministry report that a small object resembling a weather balloon had been seen over the north of the country, close to the border with Ukraine. In a statement, it said that "given the weather conditions and the impossibility of observing and identifying the object and its flight path," the airspace had been closed