The rupee today breached the 56-mark and was down 13 paise to trade at fresh three-week low of 56 rupee 10 paise against the US dollar. The fall in rupee was attributed to strong demand for the American currency from banks and importers, particularly oil firms.The rupee had lost 65 paise to 55.97 in the previous session, its lowest closing in over three weeks, against dollar.