The rupee weakened by 4 paise to 64(point)20 against the US dollar in early trade today on increased month-end demand for the American currency from importers at the Interbank Foreign Exchange.The rupee had eased from a 21-month high to close 5 paise lower at 64.16 against the dollar in yesterday's trade on fresh demand for the American currency from importers. Meanwhile, the benchmark BSE Sensex fell by 82.21 points to 29,947 in early trade. The Nifty at NSE was also down 35 points at 9307.