Mumbai: The rupee declined by 22 paise to Rs 51.74 per US dollar in early trade on the Interbank Foreign Exchange on Monday due to appreciation of the US currency against the euro and other currencies overseas.

Traders said dollar gained against the euro on renewed debt concerns in the region after rating agency Standard and Poor's cut the rating of nine European nations.

Meanwhile, the BSE benchmark Sensex was down by 64.50 points, or 0.40 per cent, at 16,090.12 in opening trade.

The rupee had gained 9 paise to close at a fresh 6-week high of Rs 51.52/53 per US dollar in the previous trading day amid increased foreign funds inflow.