Thursday, in an early, the rupee fall down by by 6 paise to 66.61 against the US currency, due to sustained demand for the dollar from importers. At the Interbank Foreign Exchange yesterday, the rupee had closed 13 paise lower at 66.55. Dealers attributed the rupee's fall to increased demand for the US currency from importers and dollar's strength against other currencies overseas. However, a higher opening in the domestic equity market capped the losses. Meanwhile, in the early session the benchmark BSE Sensex rose 125.76 points, or 0.50 per cent, to 25,227.49.