Rupee weakened by another 15 paise to 68.21 against the dollar in early trade at the Interbank Foreign Exchange market on increased month-end demand for the US currency from importers amid sustained foreign fund outflows. Yesterday, the rupee had dropped by 32 paise to close at 68.06 against the dollar.Meanwhile, the benchmark BSE Sensex was trading higher by 70 points at 26,283 in morning trade.